In Situ Photodeposition of Cobalt Phosphate (CoHxPOy) on CdIn2S4 Photocatalyst for Accelerated Hole Extraction and Improved Hydrogen Evolution

Abstract

The ternary metal sulfide CdIn2S4 (CIS) has great application potential in solar-to-hydrogen conversion due to its suitable band gap, good stability and low cost. However, the photocatalytic hydrogen (H2) evolution performance of CIS is severely limited by the rapid electron–hole recombination originating from the slow photogenerated hole transfer kinetics. Herein, by simply depositing cobalt phosphate (CoHxPOy, noted as Co-Pi), a non-precious co-catalyst, an efficient pathway for accelerating the hole transfer process and subsequently promoting the H2 evolution reaction (HER) activity of CIS nanosheets is developed. X-ray photoelectron spectroscopy (XPS) reveals that the Co atoms of Co-Pi preferentially combine with the unsaturated S atoms of CIS to form Co-S bonds, which act as channels for fast hole extraction from CIS to Co-Pi. Electron paramagnetic resonance (EPR) and time-resolved photoluminescence (TRPL) showed that the introduction of Co-Pi on ultrathin CIS surface not only increases the probability of photogenerated holes arriving the catalyst surface, but also prolongs the charge carrier’s lifetime by reducing the recombination of electrons and holes. Therefore, Co-Pi/CIS exhibits a satisfactory photocatalytic H2 evolution rate of 7.28 mmol g−1 h−1 under visible light, which is superior to the pristine CIS (2.62 mmol g−1 h−1) and Pt modified CIS (3.73 mmol g−1 h−1).

Rational Photodeposition of Cobalt Phosphate on Flower-like ZnIn2S4 for Efficient Photocatalytic Hydrogen Evolution

“…For Z5CP composites, the XRD diffraction curve closely resembles that of ZIS except that there is a faint peak at 55.6° belonging to the (202) face of hexagonal ZIS, indicating that ZIS remains a stable crystal structure after coupling with Co-Pi [ 39 ]. However, in the Z5CP composite, the characteristic diffraction peak of Co-Pi is not observed due to the amorphous nature of in situ photodeposition of Co-Pi [ 40 , 41 ]. The optical characteristics of the photocatalysts are analyzed by UV-visible diffuse reflection spectroscopy (DRS).…”

Fabrication of Bi2O3/Bismuth Titanates Modified with Metal–Organic Framework-In2S3/CdIn2S4 Materials for Electrocatalytic H2 Production and Its Photoactivity

“…Concretely, it was observed the typical irregular flower-type architectures were widely reported for the CdIn 2 S 4. − …”

Advanced Photocatalytic Nanomaterials for Energy Conversion and Environmental Remediation

“…These eleven papers were devoted to achieving high-efficiency photocatalysts by broadening the light absorption range, inhibiting the photo-induced electrons and holes recombination, and promoting the extraction of photo-induced charges for chemical reactions. The strategies include defect engineering [1], element doping [2,3], morphology manipulation [3,4], and binary and ternary composite fabrication [5][6][7][8][9][10][11]. Herein, we will provide a brief introduction to these works.…”

“…In comparison with the non-selectively deposed Pt nanoparticles, the highly dispersed Pt co-catalyst performs significantly better in promoting the photocatalytic hydrogen production of g-C 3 N 4 . Cai et al [10] deposited a CoH x PO y co-catalyst on CdIn 2 S 4 nanosheets. The CoH x PO y accelerates the hole transfer and inhibits the electron and hole recombination, thus promoting the photocatalytic hydrogen evolution reaction activity under visible light.…”