Direct evidence of the efficient hole collection process of the CoO_x cocatalyst for photocatalytic reactions: a surface photovoltage study

Abstract

The authentic effect of a cocatalyst in photocatalytic reaction is one of the major to issues in photocatalysis research. Herein, the efficient hole-collecting role of CoOx cocatalyst grown on TiO2-nanotubes has been directly proved by surface photovoltage (SPV) spectroscopy. Transient SPV measurement provides evidence for the CoOx cocatalyst that could significantly prolong the life-time of photogenerated holes. Furthermore, it is proposed the hole-collecting effect can be attributed to the work function difference between TiO2 and CoOx interface. These findings demonstrates that the development of cocatalyst with suitable work function can be a general strategy for photoconversion applications.

Enhanced Photocatalytic Hydrogen Evolution of NiCoP/g‐C3N4 with Improved Separation Efficiency and Charge Transfer Efficiency

“…The transient photovoltage under a 355 nm pulse laser was also measured with the injection of triethanolamine–water solution into the testing system. The enhanced photovoltage intensity of 50 mg NiCoP/g‐C 3 N 4 , compared to that of bare g‐C 3 N 4 , with an obvious negative signal indicates the photogenerated electrons transfer to the surface of g‐C 3 N 4 in the presence of the electron sacrificial donor . The above results are in good accordance with the photocatalytic performance.…”

Engineering of 2D/2D MoS2/CdxZn1−xS Photocatalyst for Solar H2 Evolution Coupled with Degradation of Plastic in Alkaline Solution

“…Moreover, the photovoltage signal of M 4.3 /C 0.5 Z 0.5 S on the time scale is delayed by near an order of magnitude, implying a long‐lived photoexcited carrier lifetime ( Figure a). [ 18 ] Accordingly, the electrochemical impedance spectrum (EIS) of M 4.3 /C 0.5 Z 0.5 S displays a much smaller semiarc than that of C 0.5 Z 0.5 S (Figure 3b). In addition, the polarization curve of M 4.3 /C 0.5 Z 0.5 S displays a lower overpotential than that of C 0.5 Z 0.5 S, indicating that the HER activity is remarkably enhanced by the MoS 2 cocatalyst (Figure 3c).…”

Probing the light harvesting and charge rectification of bismuth nanoparticles behind the promoted photoreactivity onto Bi/BiOCl catalyst by (in-situ) electron microscopy

“…where X is the absolute electronegativity of the semiconductor, E c the energy of free electrons on hydrogen scale (4.5 eV) and E g the band gap of the semiconductor [49].The band edge potentials of CB and VB have been theoretically speculated at -1.1 V and 0.32 V with respect to the standard hydrogen electrode (SHE) potential, respectively (Table S2, supplementary data). Therefore the Bi/BiOCl interface might be considered as a typical staggered gap (type II) band alignment as shown in Fig.…”