Change in the Magnetic Domain Alignment Process at the Onset of a Frustrated Magnetic State in Ferrimagnetic La2Ni(Ni1/3Sb2/3)O6 Double Perovskite

We have performed a combined study of magnetization hysteresis loops and time dependence of the magnetization in a broad temperature range for the ferrimagnetic La2Ni(Ni1/3Sb2/3)O6 double perovskite. This material has a ferrimagnetic order transition at ~100 K and at lower temperatures (~ 20 K) shows the signature of a frustrated state due to the presence of two competing magnetic exchange interactions. The temperature dependence of the coercive field shows an important upturn below the point where the frustrated state sets in. The use of the magnetization vs. applied magnetic field hysteresis data, together with the magnetization vs. time data provides a unique opportunity to distinguish between different scenarios for the low temperature regime. From our analysis, a strong domain wall pinning results the best scenario for the low temperature regime. For temperatures larger than 20K the adequate scenario seems to correspond to a weak domain wall pinning.Comment: 4 pages, 5 figures included. Manuscript submitted to IEEE Transactions on Magnetics, proceedings of the LAW3M 2013 conferenc

Magnetic properties of the double perovskites LaPbMSbO6 (M = Mn, Co and Ni)

New double perovskites LaPbMSbO6, where M2+ = Mn2+, Co2+, and Ni2+, were synthesized as polycrystals by an aqueous synthetic route at temperatures below 1000 oC. All samples are monoclinic, space group P21/n, as obtained from Rietveld analysis of X-ray powder diffraction patterns. The distribution of M2+ and Sb5+ among the two octahedral sites have 3% of disorder for M2+ = Ni2+, whereas for M2+ = Mn2+ and Co2+ less disorder is found. The three samples have an antiferromagnetic transition, due to the antiferromagnetic coupling between M2+ through super-superexchange paths M2+ - O2- - Sb5+ - O2- - M2+. Transition temperatures are low: 8, 10 and 17 K for Mn2+, Co2+, and Ni2+ respectively, as a consequence of the relatively long distances between the magnetic ions M2+. Besides, for LaPbMnSbO6 a small transition at 45 K was found, with ferrimagnetic characteristics, possibly as a consequence of a small disorder between Mn2+ and Sb5+. This disorder would give additional and shorter interaction paths: superexchange Mn2+ - O2- - Mn2+.Comment: 4 pages, 4 figures included. Manuscript submitted to IEEE Transactions on Magnetics, proceedings of the LAW3M 2013 conferenc

Tailoring the ground state of the ferrimagnet La2Ni(Ni1/3Sb2/3)O6

We report on the magnetic and structural properties of La2Ni(Ni1/3Sb2/3)O6 in polycrystal, single crystal and thin film samples. We found that this material is a ferrimagnet (Tc ~ 100 K) which possesses a very distinctive and uncommon feature in its virgin curve of the hysteresis loops. We observe that bellow 20 K it lies outside the hysteresis cycle, and this feature was found to be an indication of a microscopically irreversible process possibly involving the interplay of competing antiferromagnetic interactions that hinder the initial movement of domain walls. This initial magnetic state is overcome by applying a temperature dependent characteristic field. Above this field, an isothermal magnetic demagnetization of the samples yield a ground state different from the initial thermally demagnetized one.Comment: 21 pages, 8 figures, submitted to JMM

Perovskite oxides: Oxygen electrocatalysis and bulk structure

Perovskite type oxides were considered for use as oxygen reduction and generation electrocatalysts in alkaline electrolytes. Perovskite stability and electrocatalytic activity are studied along with possible relationships of the latter with the bulk solid state properties. A series of compounds of the type LaFe(x)Ni1(-x)O3 was used as a model system to gain information on the possible relationships between surface catalytic activity and bulk structure. Hydrogen peroxide decomposition rate constants were measured for these compounds. Ex situ Mossbauer effect spectroscopy (MES), and magnetic susceptibility measurements were used to study the solid state properties. X ray photoelectron spectroscopy (XPS) was used to examine the surface. MES has indicated the presence of a paramagnetic to magnetically ordered phase transition for values of x between 0.4 and 0.5. A correlation was found between the values of the MES isomer shift and the catalytic activity for peroxide decomposition. Thus, the catalytic activity can be correlated to the d-electron density for the transition metal cations

Magnetization reversal in mixed ferrite-chromite perovskites with non magnetic cation on the A-site

In this work, we have performed Monte Carlo simulations in a classical model for RFe$_{1-x}$Cr$_x$O$_3$ with R=Y and Lu, comparing the numerical simulations with experiments and mean field calculations. In the analyzed compounds, the antisymmetric exchange or Dzyaloshinskii-Moriya (DM) interaction induced a weak ferromagnetism due to a canting of the antiferromagnetically ordered spins. This model is able to reproduce the magnetization reversal (MR) observed experimentally in a field cooling process for intermediate $x$ values and the dependence with $x$ of the critical temperatures. We also analyzed the conditions for the existence of MR in terms of the strength of DM interactions between Fe$^{3+}$ and Cr$^{3+}$ ions with the x values variations.Comment: 8 pages, 7 figure

Electronic and structural study of Pt-modified Au vicinal surfaces: a model system for Pt–Au catalysts

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOTwo single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (θPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on θPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings. © 2014 The Owner Societies.Two single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (yPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on yPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings.Two single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (yPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on yPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings.16261332913339FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO07/54829-5; 2011/12.566-3; 2012/16860-6160172/2011-0Greeley, J., Stephens, I.E.L., Bondarenko, A.S., Johansson, T.P., Hansen, H.A., Jaramillo, T.F., Rossmeisl, J., Nørskov, J.K., (2009) Nat. Chem., 1, pp. 552-556Wu, G., More, K.L., Johnston, C.M., Zelenay, P., (2011) Science, 332, pp. 443-447Chu, Y.H., Shul, Y.G., (2010) Int. J. Hydrogen Energy, 35, pp. 11261-11270Kowal, A., Li, M., Shao, M., Sasaki, K., Vukmirovic, M.B., Zhang, J., Marinkovic, N.S., Adzic, R.R., (2009) Nat. Mater., 8, pp. 325-330Xu, C.W., Su, Y.Z., Tan, L.L., Liu, Z.L., Zhang, J.H., Chen, S.A., Jiang, S.P., (2009) Electrochim. Acta, 54, pp. 6322-6326Colmati, F., Antolini, E., Gonzalez, E.R., (2008) J. Alloys Compd., 456, pp. 264-270Antolini, E., (2007) J. Power Sources, 170, pp. 1-12Colmati, F., Antolini, E., Gonzalez, E.R., (2006) J. Power Sources, 157, pp. 98-103Stamenkovic, V.R., Mun, B.S., Mayrhofer, K.J.J., Ross, P.N., Markovic, N.M., (2006) J. Am. Chem. Soc., 128, pp. 8813-8819Freund, H.-J., Pacchioni, G., (2008) Chem. Soc. Rev., 37, pp. 2224-2242Kim, Y., Kim, H.J., Kim, Y.S., Choi, S.M., Seo, M.H., Kim, W.B., (2012) J. Phys. Chem. C, 116, pp. 18093-18100Kwon, Y., Birdja, Y., Spanos, I., Rodriguez, P., Koper, M.T.M., (2012) ACS Catal., 2, pp. 759-764Freitas, R.G., Pereira, E.C., (2010) Electrochim. Acta, 55, pp. 7622-7627Colmati, F., Tremiliosi, G., Gonzalez, E.R., Berna, A., Herrero, E., Feliu, J.M., (2009) Phys. Chem. Chem. Phys., 11, pp. 9114-9123Repain, V., Baudot, G., Ellmer, H., Rousset, S., (2002) Europhys. Lett., 58, p. 730Repain, V., Berroir, J.M., Rousset, S., Lecoeur, J., (1999) Europhys. Lett., 47, p. 435Nahas, Y., Repain, V., Chacon, C., Girard, Y., Rousset, S., (2010) Surf. Sci., 604, pp. 829-833Rohart, S., Girard, Y., Nahas, Y., Repain, V., Rodary, G., Tejeda, A., Rousset, S., (2008) Surf. Sci., 602, pp. 28-36Rohart, S., Baudot, G., Repain, V., Girard, Y., Rousset, S., Bulou, H., Goyhenex, C., Proville, L., (2004) Surf. Sci., 559, pp. 47-62Axel, G., (2009) J. Phys.: Condens. Matter, 21, p. 084205Rodriguez, J., (1996) Surf. Sci. Rep., 24, pp. 223-287Eyrich, M., Diemant, T., Hartmann, H., Bansmann, J., Behm, R.J., (2012) J. Phys. Chem. C, 116, pp. 11154-11165Bowker, M., (1995) Chem. Vap. Deposition, 1, p. 90Xu, J.B., Zhao, T.S., Yang, W.W., Shen, S.Y., (2010) Int. J. Hydrogen Energy, 35, pp. 8699-8706Wang, J., Yin, G., Wang, G., Wang, Z., Gao, Y., (2008) Electrochem. Commun., 10, pp. 831-834Horcas, I., Fernandez, R., Gomez-Rodriguez, J.M., Colchero, J., Gomez-Herrero, J., Baro, A.M., (2007) Rev. Sci. Instrum., 78, pp. 013705-013708Doniach, S., Sunjic, M., (1970) J. Phys. C: Solid State Phys., 3, p. 285Hörnström, S.E., Johansson, L., Flodström, A., Nyholm, R., Schmidt-May, J., (1985) Surf. Sci., 160, pp. 561-570Shevchik, N.J., (1974) Phys. Rev. Lett., 33, p. 1336Powell, C.J., (2012) J. Electron Spectrosc. Relat. Phenom., 185, pp. 1-3Rousset, S., Repain, V., Baudot, G., Garreau, Y., Lecoeur, J., (2003) J. Phys.: Condens. Matter, 15, p. 3363Prévot, G., Girard, Y., Repain, V., Rousset, S., Coati, A., Garreau, Y., Paul, J., Narasimhan, S., (2010) Phys. Rev. B: Condens. Matter Mater. Phys., 81, p. 075415Repain, V., Rohart, S., Girard, Y., Tejeda, A., Rousset, S., (2006) J. Phys.: Condens. Matter, 18, p. 17Repain, V., Baudot, G., Ellmer, H., Rousset, S., (2002) Mater. Sci. Eng., B, 96, pp. 178-187Repain, V., Berroir, J.M., Rousset, S., Lecoeur, J., (2000) Surf. Sci., 447, pp. 152-L156Campiglio, P., Repain, V., Chacon, C., Fruchart, O., Lagoute, J., Girard, Y., Rousset, S., (2011) Surf. Sci., 605, pp. 1165-1169Prieto, M.J., Carbonio, E.A., Landers, R., De Siervo, A., (2013) Surf. Sci., 617, pp. 87-93Antczak, G., Ehrlich, G., (2010) Surface Diffusion: Metals, Metal Atoms, and Clusters, , Cambridge Univesrity Press, New YorkKim, S.Y., Lee, I.-H., Jun, S., (2007) Phys. Rev. B: Condens. Matter Mater. Phys., 76, p. 245407Liu, Y.B., Sun, D.Y., Gong, X.G., (2002) Surf. Sci., 498, pp. 337-342Prévot, G., Barbier, L., Steadman, P., (2010) Surf. Sci., 604, pp. 1265-1272Pedersen M.Ø, Helveg, S., Ruban, A., Stensgaard, I., Lægsgaard, E., Nørskov, J.K., Besenbacher, F., (1999) Surf. Sci., 426, pp. 395-409Gohda, Y., Groß, A., (2007) Surf. Sci., 601, pp. 3702-3706Pastor, E., Rodriguez, J.L., Iwasita, T., (2002) Electrochem. Commun., 4, pp. 959-962Keister, J.K., Rowe, J.E., Kolodziej, J.J., Madey, T.E., (2000) J. Vac. Sci. Tech. B, 18, pp. 2174-2178. , 10.1116/1.1305872Martin, R., Gardner, P., Bradshaw, A.M., (1995) Surf. Sci., 342, pp. 69-84Bare, S.R., Hofmann, P., King, D.A., (1984) Surf. Sci., 144, pp. 347-369Yamagishi, S., Fujimoto, T., Inada, Y., Orita, H., (2005) J. Phys. Chem. B, 109, pp. 8899-8908Watanabe, S., Inukai, J., Ito, M., (1993) Surf. Sci., 293, pp. 1-9Sarkar, A., Kerr, J.B., Cairns, E.J., (2013) ChemPhysChem, 14, pp. 2132-2142Du, B., Zaluzhna, O., Tong, Y.J., (2011) Phys. Chem. Chem. Phys., 13, pp. 11568-11574Auten, B.J., Lang, H., Chandler, B.D., (2008) Appl. Catal., B, 81, pp. 225-235Gohda, Y., Groß, A., (2007) J. Electroanal. Chem., 607, pp. 47-53Kobiela, T., Moors, M., Linhart, W., Cebula, I., Krupski, A., Becker, C., Wandelt, K., (2010) Thin Solid Films, 518, pp. 3650-3657Petkov, V., Wanjala, B.N., Loukrakpam, R., Luo, J., Yang, L., Zhong, C.-J., Shastri, S., (2012) Nano Lett., 12, pp. 4289-4299Authors thank Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP-07/54829-5) and Conselho Nacional de Pesquisa (CNPq) for financial support. Specially thank to L. H. Lima for experimental assistance with STM measurements and Prof. G. Tremiliosi-Filho for lending the Au(332) crystal. MJP, SF and EAC thank FAPESP and CNPq for the fellowships granted (Procs. FAPESP 2011/12.566-3 and 2012/16860-6; Proc. CNPq 160172/2011-0)

Room-temperature tuning of magnetic anisotropy in samarium-thulium orthoferrites

Rare-earth orthoferrites (RFeO3) provide a flexible playground for magnetic materials design, combining the magnetic properties arising from complex interactions between R3+ and Fe3+ cations within the robust framework of the perovskite structure. The most important magnetic property common to most orthoferrites is a spin reorientation transition in which the magnetic moments of Fe3+ cations rotate with respect to a crystallographic axis. SmFeO3 is unique among orthoferrites due to its high-temperature spin reorientation. It is possible to tune the spin reorientation transition to occur at room temperature by replacing Sm with Tm in the Sm0.70Tm0.30FeO3 perovskite. In this study, we show how small changes in composition in the Sm1-xTmxFeO3 (x=0.30-0.50) series provide a high degree of control over the magnetic properties. This work also offers a rather unusual look into the magnetic structure of a samarium-based perovskite by means of neutron powder diffraction, which was made possible by using Sm152. The combination of these results and magnetization measurements allowed the construction of the magnetic phase diagram of the series.Fil: Bolletta, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Cuello, Gabriel Julio. Institut Laue Langevin; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nassif, Vivian. Universite Grenoble Alpes; FranciaFil: Suard, Emmanuelle. Institut Laue Langevin; FranciaFil: Kurbakov, Alexander I.. No especifíca;Fil: Maignan, Antoine. No especifíca;Fil: Martin, Christine. No especifíca;Fil: Carbonio, Raul Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin

Oxidation states of Fe in LaNi₁₋ₓ Feₓ O₃

The distributoin of oxidation states in perovskites of the type LaA₁₋ₓ BₓO₃ (A and B transition metal ions) can be “tailored” byx variation. In paticular, in LaNiO₃ it has been shown that Fe substitution for Ni foces some Ni³⁺ into Ni²⁺, while some Fe³⁺ changes into the unusual Fe⁴⁺ state. In addition, the existence of mixed oxidation states of Fe and/or Ni in LaNi₁₋ₓ FeₓO₃ has been related to its catalytic activity in hydrogen peroxide decomposition. The Fe⁴⁺ population, obtained using Mossbauer spectroscopy, was found to be constant for all the analyzed annealing temperatures forx=0.25 concentration, where the isomer shift difference for both states is the highest and the catalytic activity is maximum.Facultad de Ciencias Exacta

Spin reorientation and metamagnetic transitions in R F e0.5 C r0.5 O3 perovskites (R=Tb, Dy, Ho, Er)

In this work we present the magnetic structures and spin reorientation (SR) transitions of the mixed orthochromite-orthoferrite perovskites RFe0.5Cr0.5O3 (R=Tb, Dy, Ho, Er). Magnetization as a function of temperature and external magnetic field as well as neutron powder diffraction measurements were used to characterize the magnetic transitions, including the SR transitions in the transition metal sublattice and the ordering of the rare earth sublattice. The studied compounds order antiferromagnetically below 270 K in a Gx configuration compatible with the Γ4 representation. As temperature decreases, all the compounds show a SR transition from Gx (Γ4) to Gz (Γ2). This transition occurs in a wide temperature range, where both magnetic configurations coexist. Below this SR, the behavior in each case depends on the rare earth. HoFe0.5Cr0.5O3 shows Ho3+ sublattice ordering at a relatively high temperature (45 K). DyFe0.5Cr0.5O3 and ErFe0.5Cr0.5O3 show a second SR transition of the transition metal sublattice, from Gz (Γ2) to Gy (Γ1) at low temperatures (15 and 8 K, respectively). Below these temperatures a metamagnetic (MM) transition is observed for these two compounds at an external magnetic field of H ≈ 7 kOe. The fact that this is only observed for compounds showing Gz (Γ2) to Gy (Γ1) transition suggests that there is a correlation between the Gy (Γ1) order and the MM transition. Finally, TbFe0.5Cr0.5O3 is a peculiar case, since it is the only compound in this family that shows a re-entrant SR to Gx (Γ4) at very low temperatures. By combining these results with previous reports on RFeO3, RCrO3, and RFe0.5Cr0.5O3, we develop a method to qualitatively estimate the SR temperature and the type of transition. We also propose a complete magnetic phase diagram containing the SR transitions and R3+ ordering temperatures for all the RFe0.5Cr0.5O3 (R=Tb, Dy, Ho, Er, Tm, Yb, and Lu) compounds.Fil: Bolletta, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Pomiro, Fernando. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Sanchez, Rodolfo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Resonancias Magnéticas; ArgentinaFil: Pomjakushin, Vladimir. Universidad Nacional de Cuyo; ArgentinaFil: Aurelio, Gabriela. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Física de Metales; ArgentinaFil: Maignan, Antoine. Université de Caen Normandie; FranciaFil: Martin, Christine. Université de Caen Normandie; FranciaFil: Carbonio, Raul Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin

Perspective Outlook on Operando Photoelectron and Absorption Spectroscopy to Probe Catalysts at the Solid Liquid Electrochemical Interface

Operando X-ray Photoelectron and Absorption Spectroscopy (XPS and XAS) using soft (up to 2 KeV) and tender (2–10 KeV) X-rays applied to study functional materials for energy conversion has gone through great development in the last years and several approaches to different cell designs combined with instrumentation development now allow successful characterization of electrode-electrolyte interfaces under working conditions. An overview of the current state and challenges are presented along with an outlook into the direction that future development should take, which we expect would allow us to expand and complete our understanding of the liquid-solid electrochemical interfaces