Search

In this work, CeO2quantum dots were anchored on the surface of oxygen defected CdWO4nanorods through a simple precipitation procedure to construct an efficient S-scheme heterojunction. The as-fabricated pristine and hybrid photocatalysts were thoroughly characterized by XRD, BET, SEM, HRTEM, and XPS analyses and applied for the photoreduction of CO2and photocatalytic hydrogen evolution under simulated sunlight irradiation. The results revealed that CH4and CO were the major products and CH3OH was detected as the side product from the photoreduction of CO2. The photoreduction yield of the heterojunction was substantially improved with the addition of CeO2as compared to the pure samples, and the heterojunction containing 40 mol % CeO2showed the highest efficiency. This improvement could be mainly ascribed to the higher reduction potential of the separated electrons and exceptional mobility of charge carriers. Additionally, the adsorption of CO2and hydroxyl groups was increased due to the increased density of oxygen vacancy sites at the interfacial contacts acting as trapping centers for photoexcited electrons. Based on the experimental and theoretical results, S-scheme charge transfer was proposed for the fabricated CdWO4-CeO2heterojunction.

Enhancing stability against photocorrosion and improving photocurrent response are the main challenges toward the development of cupric oxide (CuO) based photocathodes for solar-driven hydrogen production. In this paper, stable and efficient CuO-photocathodes have been developed using in situ materials engineering and through gold–palladium (Au–Pd) nanoparticles deposition on the CuO surface. The CuO photocathode exhibits a photocurrent generation of ∼3 mA/cm2at 0 V v/s RHE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and X-ray spectroscopy (XPS) confirm the formation of oxygen-rich (O-rich) CuO film which demonstrates a highly stable photocathode with retained photocurrent of ∼90% for 20 min. The influence of chemical composition on the photocathode performance and stability has been discussed in detail. In addition, O-rich CuO photocathodes deposited with Au–Pd nanostructures have shown enhanced photoelectrochemical performance. Linear scan voltammetry characteristic shows ∼25% enhancement in photocurrent after Au–Pd deposition and reaches ∼4 mA/cm2at “0” V v/s RHE. Hydrogen evolution rate significantly depends on the elemental composition of CuO and metal nanostructure. The present work has demonstrated a stable photocathode with high photocurrent for visible-light-driven water splitting and hydrogen production.