Engineering Surface Passivation and Hole Transport Layer on Hematite Photoanodes Enabling Robust Photoelectrocatalytic Water Oxidation

Regulation of charge transport at the molecular level is essential to elucidating the kinetics of junction photoelectrodes across the heterointerface for photoelectrochemical (PEC) water oxidation. Herein, an integrated photoanode as the prototype was constructed by use of a 5,10,15,20-tetrakis(4-carboxyphenyl) porphyrin-cobalt molecule (CoTCPP) and ZnO on hematite (α-Fe2O3) photoanode. CoTCPP molecules serve as a typical hole transport layer (HTL), accelerating the transport of the photogenerated holes to oxygen evolution cocatalysts (OECs). Meanwhile, ZnO as the surface passivation layer (SPL) can passivate the interfacial state and reduce the level of electron leakage from hematite into the electrolyte. After the integration of OECs, the state-of-the-art α-Fe2O3/ZnO/CoTCPP/OECs photoanode exhibits a distinguished photocurrent density and excellent stability in comparison with pristine α-Fe2O3. The simultaneous incorporation of a ZnO and CoTCPP dual interlayer can effectively modulate the interfacial photoinduced charge transfer for PEC reaction. This work provides in-depth insights into interfacial charge transfer across junction electrodes and identifies the critical roles of solar PEC conversion

BiVO₄‑Based Heterojunction Photocathode for High-Performance Photoelectrochemical Hydrogen Peroxide Production

Photoelectrochemical (PEC) cells provide a promising solution for the synthesis of hydrogen peroxide (H2O2). Herein, an integrated photocathode of p-type BiVO4 (p-BVO) array with tetragonal zircon structure coupled with different metal oxide (MOx, M = Sn, Ti, Ni, and Zn) heterostructure and NiNC cocatalyst (p-BVO/MOx/NiNC) was synthesized for the PEC oxygen reduction reaction (ORR) in production of H2O2. The p-BVO/SnO2/NiNC array achieves the production rate 65.46 μmol L–1 h–1 of H2O2 with a Faraday efficiency (FE) of 76.12%. Combined with the H2O2 generation of water oxidation from the n-type Mo-doped BiVO4 (n-Mo:BVO) photoanode, the unbiased photoelectrochemical cell composed of a p-BVO/SnO2/NiNC photocathode and n-Mo:BVO photoanode achieves a total FE of 97.67% for H2O2 generation. The large area BiVO4-based tandem cell of 3 × 3 cm2 can reach a total H2O2 production yield of 338.84 μmol L–1. This work paves the way for the rational design and fabrication of artificial photosynthetic cells for the production of liquid solar fuel

Development of Solution-Processed ZnO Nanorod Arrays Based Photodetectors and the Improvement of UV Photoresponse via AZO Seed Layers

Designing a rational structure and developing an efficient fabrication technique for bottom-up devices offer a promising opportunity for achieving high-performance devices. In this work, we studied how Al-doped ZnO (AZO) seed layer films influence the morphology and optical and electrical properties for ZnO aligned nanorod arrays (NRs) and then the performance of ZnO NRs based ultraviolet photodetectors (UV PDs) with Au/ZnO NRs Schottky junctions and p-CuSCN/n-ZnO NRs heterojunctions. The PD with AZO thin film with 0.5 at. % Al doping (named as AZO (0.5%)) exhibited more excellent photoresponse properties than that with pristine ZnO and AZO (1%) thin films. This phenomenon can be ascribed to the good light transmission of the AZO layer, increased density of the NRs, and improved crystallinity of ZnO NRs. The PDs based on CuSCN/ZnO NRs heterojunctions showed good rectification characteristics in the dark and self-powered UV photoresponse properties with excellent stability and reproducibility under low-intensity illumination conditions. A large responsivity located at 365 nm of 22.5 mA/W was achieved for the PD with AZO (0.5%) thin film without applied bias. The internal electric field originated from p-CuSCN/n-ZnO NRs heterojunctions can separate photogenerated carriers in ZnO NRs and drift toward the corresponding electrode

TiO₂ Nanorod Arrays Based Self-Powered UV Photodetector: Heterojunction with NiO Nanoflakes and Enhanced UV Photoresponse

The self-powered ultraviolet photodetectors (UV PDs) have attracted increasing attention due to their potential applications without consuming any external power. It is important to obtain the high-performance self-powered UV PDs by a simple method for the practical application. Herein, TiO₂ nanorod arrays (NRs) were synthesized by hydrothermal method, which were integrated with p-type NiO nanoflakes to realize a high performance pn heterojunction for the efficient UV photodetection. TiO<i>_x</i> thin film can improve the morphological and carrier transport properties of TiO₂ NRs and decrease the surface and defect states, resulting in the enhanced photocurrent of the devices. NiO/TiO₂ nanostructural heterojunctions show excellent rectifying characteristics (rectification ratio of 2.52 × 10⁴ and 1.45 × 10⁵ for NiO/TiO₂ NRs and NiO/TiO₂ NRs/TiO<i>_x</i>, respectively) with a very low reverse saturation current. The PDs based on the heterojunctions exhibit good spectral selectivity, high photoresponsivity, and fast response and recovery speeds without external applied bias under the weak light radiation. The devices demonstrate good stability and repeatability under UV light radiation. The self-powered performance could be attributed to the proper built-in electric field of the heterojunction. TiO₂ NRs and NiO nanoflakes construct the well-aligned energy-band structure. The enhanced responsivity and detectivity for the devices with TiO<i>_x</i> thin films is related to the increased interfacial charge separation efficiency, reduced carrier recombination, and relatively good electron transport of TiO₂ NRs

Spontaneous action potential durations (APD).

<p>(A), Representative monophasic action potentials recorded from LV. (B), Compared with controls, the APD₉₀ was prolonged in MI+D rats and MI rats. ^★p<0.01 vs Sham group, <b>^§</b>p<0.05 vs MI group.</p

The depressive-like behaviors evaluated by the sucrose preference test and the open field test.

<p>After 4 weeks of chronic mild stress, the rats showed a decrease in sucrose preference (A) and deficiency in spontaneous locomotor activity, included rearing (B), travelled distance (C) and exploration activity (D). <b>^★</b>p<0.01 vs Sham group, <b>^★</b>p<0.01 and <b>^§</b>p<0.05 vs MI group.</p

Echocardiogram parameters of left ventricular structure and function.

<p>LVEDD, left ventricular end-diastolic diameter; LVESD, left ventricular end-systolic diameter; LVWT, left ventricular wall thickness; LVEF, left ventricular ejection fraction; FS, fractional shortening; ^★p<0.01 vs Sham group, <b>^#</b>p<0.01 and <b>^§</b>p<0.05vs MI group.</p

The comparisons in survival rate and body weight gain.

<p>(A), The survival rate was not different among groups (p = 0.09). The MI+D rats displayed an attenuated body weight gain (B), increased heart weight (C) and increased heart weight ratio (D). ^★p<0.01 and <b></b>p<0.05 indicate MI+D group or MI group vs Sham group, <b>^#</b>p<0.01 and <b>^§</b>p<0.05 indicate MI+D group vs MI group.</p

Inducibility of ventricular arrhythmia (VA) by programmed electrical stimulation.

<p>(A) and (B), Representative action potential (AP) traces from left ventricle (LV) in a Sham rat and a depression rat. No VA could be elicited by programmed stimulation. (C), Representative AP traces from LV in an MI rat. While pacing at S₁-S₂ of 80 ms, a normal AP was captured and propagated (a). An impulse was delivered at S₁-S₂ of 50 ms, and PVC was elicited (b). When delivered at shorter interval of 40 ms, a transient VA was induced (c). (D), Representative AP traces from an MI+D rat, while pacing at S₁-S₂ of 80 ms and 50 ms, transient VA was induced (a and b). When delivered at S₁-S₂ of 40 ms, a sustained VA was elicited (c).</p

Quantification of plasma epinephrine and norepinephrine, cardiac tyrosine hydroxylase, and immunohistochemical staining for tyrosine hydroxylase nerve fiber.

<p>(A), The concentrations of epinephrine and norepinephrine were higher in MI+D rats than MI rats, but only norepinephrine was higher in D rats versus Sham rats. (B) and (C), Compared with MI rats, the sympathetic innervation of the border regions was particularly prominent in MI+D rats, and sympathetic hyperinnervation was also observed in D rats.^★p<0.01 vs Sham group, ^#p<0.01 and ^§p<0.05 vs MI group.</p