Electrolyte Salts and Additives Regulation Enables High Performance Aqueous Zinc Ion Batteries: A Mini Review

Aqueous zinc ion batteries (ZIBs) are regarded as one of the most ideally suited candidates for large-scale energy storage applications owning to their obvious advantages, that is, low cost, high safety, high ionic conductivity, abundant raw material resources, and eco-friendliness. Much effort has been devoted to the exploration of cathode materials design, cathode storage mechanisms, anode protection as well as failure mechanisms, while inadequate attentions are paid on the performance enhancement through modifying the electrolyte salts and additives. Herein, to fulfill a comprehensive aqueous ZIBs research database, a range of recently published electrolyte salts and additives research is reviewed and discussed. Furthermore, the remaining challenges and future directions of electrolytes in aqueous ZIBs are also suggested, which can provide insights to push ZIBs’ commercialization

AuPt Nanoparticles/ Multi-Walled Carbon Nanotubes Catalyst as High Active and Stable Oxygen Reduction Catalyst for Al-Air Batteries

A series of AuPt nanoparticles supported on multi-walled carbon nanotubes (AuxPt/MWNTs) catalysts with ultrafine distribution (d ≈ 3.0 nm) were synthesized for Al-air battery cathode to enhance the oxygen reduction reaction. Among them, Au0.67Pt/MWNTs catalyst with metal loading of 10.2wt.% (Au:4.1wt.%, Pt:6.1wt.%) exhibited a superior ORR catalytic activity and competitive durability to 20wt.% Pt/C catalyst. When applied as Al-air battery, appropriate increasing Au loading encourage better battery performance. Au1.68Pt/MWNTs with 8.95wt.% of Au and as little as 5.3 wt.% Pt content exhibit larger specific capacity (921 mAh g-1) and power density (146.8 mW cm-2) as well as better durability than 20 wt.% Pt/C catalyst when it is assembled as cathode in Al-air battery

Porous Bilayer Electrode‐Guided Gas Diffusion for Enhanced CO 2 Electrochemical Reduction

Comparing with the massive efforts in developing innovative catalyst materials system and technologies, structural design of cells has attracted less attention on the road toward high‐performance electrochemical CO2 reduction reaction (eCO2RR). Herein, a hybrid gas diffusion electrode‐based reaction cell is proposed using highly porous carbon paper (CP) and graphene aerogels (GAs), which is expected to offer directional diffusion of gas molecules onto the catalyst bed, to sustain a high performance in CO2 conversion. The above‐mentioned hypothesis is supported by the experimental and simulation results, which show that the CP + GA combined configuration increases the Faraday efficiency (FE) from ≈60% to over 94% toward carbon monoxide (CO) and formate production compared with a CP only cell with Cu2O as the catalyst. It also suppresses the undesirable side reaction–hydrogen evolution over 65 times than the conventional H‐type cell (H‐cell). By combining with advanced catalysts with high selectivity, a 100% FE of the cell with a high current density can be realized. The described strategy sheds an extra light on future development of eCO2RR with a structural design of cell‐enabled high CO2 conversion

Plasmonic Au nanoparticles supported on both sides of TiO2 hollow spheres for maximising photocatalytic activity under visible light

A strategy of intensifying the visible light harvesting ability of anatase TiO2 hollow spheres (HSs) was developed, in which both sides of TiO2 HSs were utilised for stabilising Au nanoparticles (NPs) through the sacrificial templating method and convex surface-induced confinement. The composite structure of single Au NP yolk-TiO2 shell-Au NPs, denoted as Au@Au(TiO2, was rendered and confirmed by the transmission electron microscopy analysis. Au@Au(TiO2 showed enhanced photocatalytic activity in the degradation of methylene blue and phenol in aqueous phase under visible light surpassing that of other reference materials such as Au(TiO2 by 77% and Au@P25 by 52%, respectively, in phenol degradation

Silver Nanoparticle/Multiwalled Carbon Nanotube Hybrid as an Efficient Electrocatalyst for Oxygen Reduction Reaction in Alkaline Medium

A facile approach is employed to synthesize Ag/MWNTs hybrids by the direct reduction of silver nitrate with presence of MWNTs, where Ag nanoparticles capped with tris(hydroxymethyl)phosphine oxide (d = 2.9 nm) are uniformly deposited on multi‐walled carbon nanotubes. The as‐synthesized Ag/MWNTs hybrids exhibit high catalytic activity toward oxygen reduction, which increases with the loading amounts of Ag nanoparticles. RDE and RRDE analyses further indicate that the Ag/MWNTs hybrids follow the same four‐electron pathway towards oxygen reduction reaction as the Pt/C catalyst, and the Ag/MWNTs hybrid (22.8 wt.%) manifests comparable catalytic activity to the 20% Pt/C catalyst, together with superior long‐term stability and methanol tolerance, demonstrating the potential application on direct methanol fuel cells as an effective oxygen reduction catalyst

Rhenium-functionalized covalent organic framework photocatalyst for efficient CO2 reduction under visible light

International audienceThe conversion of carbon dioxide (CO 2) into value-added chemicals under photochemical conditions has attracted increasing attention in recent years. One of the great challenges is to develop novel active catalysts under visible light irradiation with sustained lifetime and high activity. In this regard, herein, we report a highly efficient, stable and recyclable photocatalyst by embedding photoactive rhenium complex (Re(CO) 5 Cl) into porous, crystalline, bipyridine-based covalent organic frameworks (COFs). The rhenium post-metallated COFs exhibits salient photocatalytic activity towards CO 2 reduction into CO under visible light. The quantity of the CO produced on Re-functionalized COFs is twice higher than that produced on the famous Re(bpy)(CO) 3 Cl (bpy = 2,2′-bipyridine) molecular photocatalyst under similar reaction conditions

Mass transfer effect to electrochemical reduction of CO₂: Electrode, electrocatalyst and electrolyte

Electrochemical carbon dioxide reduction reaction (eCO2RR) to value-added chemicals is considered as a promising strategy for CO2 conversion with economic and environmental benefits. Recently, investigations in eCO2RR to produce chemicals as energy or chemical industrial feedstock have received much attention. The eCO2RR generally occurs at the interface between electrode/electrocatalyst and electrolyte including charge transfer, phase transformation and mass transport. One of key problems in the electrochemical reaction is mass transfer limitation owing to the gaseous property of CO2 with low concentration on the surface of electrode/electrocatalyst. Several strategies were employed to improve mass transfer in the past years, including electrochemical reactors, electrodes, electrocatalysts and electrolytes, etc. which could low reaction barriers so adequately that reaction rates can be realized that are sufficient for eCO2RR. This article comprehensively reviewed development related to mass transfer study of CO2, including the mechanism of mass transfer of CO2, and main factors (electrodes, electrocatalysts and electrolytes) on two-phase or multi-phase interface during eCO2RR. The article is not aim at providing a comprehensive review of technical achievements towards eCO2RR technology, but rather to highlight electrode, catalyst, electrolyte, and other factors, which can understand the above components or factors' effects towards mass transfer investigations, to decouple mass transfer limitations and improve the performance of electrochemical CO2 conversion. Furthermore, the challenges and perspectives for mass transfer to eCO2RR are proposed.</p

Biocompatible Ti3Au–Ag/Cu thin film coatings with enhanced mechanical and antimicrobial functionality

Abstract Background Biofilm formation on medical device surfaces is a persistent problem that shelters bacteria and encourages infections and implant rejection. One promising approach to tackle this problem is to coat the medical device with an antimicrobial material. In this work, for the first time, we impart antimicrobial functionality to Ti3Au intermetallic alloy thin film coatings, while maintaining their superior mechanical hardness and biocompatibility. Methods A mosaic Ti sputtering target is developed to dope controlled amounts of antimicrobial elements of Ag and Cu into a Ti3Au coating matrix by precise control of individual target power levels. The resulting Ti3Au-Ag/Cu thin film coatings are then systematically characterised for their structural, chemical, morphological, mechanical, corrosion, biocompatibility-cytotoxicity and antimicrobial properties. Results X-ray diffraction patterns reveal the formation of a super hard β-Ti3Au phase, but the thin films undergo a transition in crystal orientation from (200) to (211) with increasing Ag concentration, whereas introduction of Cu brings no observable changes in crystal orientation. Scanning and transmission electron microscopy analysis show the polyhedral shape of the Ti3Au crystal but agglomeration of Ag particles between crystal grains begins at 1.2 at% Ag and develops into large granules with increasing Ag concentration up to 4.1 at%. The smallest doping concentration of 0.2 at% Ag raises the hardness of the thin film to 14.7 GPa, a 360% improvement compared to the ∼4 GPa hardness of the standard Ti6Al4V base alloy. On the other hand, addition of Cu brings a 315—330% improvement in mechanical hardness of films throughout the entire concentration range of 0.5—7.1 at%. The thin films also show good electrochemical corrosion resistance and a > tenfold reduction in wear rate compared to Ti6Al4V alloy. All thin film samples exhibit very safe cytotoxic profiles towards L929 mouse fibroblast cells when analysed with Alamar blue assay, with ion leaching concentrations lower than 0.2 ppm for Ag and 0.08 ppm for Cu and conductivity tests reveal the positive effect of increased conductivity on myogenic differentiation. Antimicrobial tests show a drastic reduction in microbial survival over a short test period of < 20 min for Ti3Au films doped with Ag or Cu concentrations as low as 0.2—0.5 at%. Conclusion Therefore, according to these results, this work presents a new antimicrobial Ti3Au-Ag/Cu coating material with excellent mechanical performance with the potential to develop wear resistant medical implant devices with resistance to biofilm formation and bacterial infection. Graphical Abstrac

Additional file 3 of Biocompatible Ti3Au–Ag/Cu thin film coatings with enhanced mechanical and antimicrobial functionality

Additional file 3: Supplementary data 3. a Table showing the corresponding slope, intercept and R2 values derived from linear fit performed on log reduction of antimicrobial bioluminescence data from Ag and Cu doped samples