The roles and mechanism of cocatalysts in photocatalytic water splitting to produce hydrogen

Recent Advances in Transition Metal Nitride‐Based Materials for Photocatalytic Applications

“…[ 14 ] Therefore, the utilization of cocatalysts can decrease the activation energy of reaction and help the promotion of these photocatalytic processes. [ 94 ] ii)Cocatalysts contribute to the electron–hole separation at the cocatalyst/semiconductor interface. As shown in Figure 1, the electrons in the CB of semiconductor photocatalyst migrate to the reductive cocatalyst and reduce the electron acceptors into reduced products.…”

“…They have optimal metal‐like properties, even better than noble metals according to density functional theory (DFT) calculation and experimental results. [ 94 ] Thus, they can play an ideal role in the photocatalytic process to transfer electrons from the surface of photocatalysts. This successfully promotes the separation of electron–hole charge pairs and prevents recombination.…”

Recent Developments of TiO2-Based Photocatalysis in the Hydrogen Evolution and Photodegradation: A Review

“…This transition of the electron leads to the generation of a positively charged carrier-hole ( ) in the valence band (Equation (1)). Also, these charge carriers can recombine among themselves (Equation (2)) [ 4 , 5 ]. …”

Photocatalytic Hydrogen Evolution Coupled with Production of Highly Value‐Added Organic Chemicals by a Composite Photocatalyst CdIn2S4@MIL‐53‐SO3Ni1/2

“…[18,19] There are many noble-metals (e. g. Pt, Ru and Pd) and transition-metals (e. g. Co, Ni and Fe) that have been introduced into the photocatalytic system as redox-active sites to improve the photocatalytic efficiency. [20,21] Even though in situ photodeposition has been one of the most convenient pathways to load cocatalyst sites, the in situ produced redoxactive metallic species is easily re-oxidized upon exposed in air and easily leached off during photocatalysis, leading to deactivate the photocatalysts and/or contaminate the reaction mixtures. [22][23][24] We have demonstrated that suspended ion catalysts (SICs) could effectively prevent leaching of metallic species and endow ionic redox-active sites freely mobile by confining ionic redox-active sites in the ionic pores of metal-organic frameworks (MOFs), which exhibited highly catalytic efficiency and stability in heterogeneous catalysis, electrocatalysis and photocatalysis.…”

“…To improve the photocatalytic performance and stability, cocatalysts were often employed as the hole and electron traps by inhibiting their recombination, lowering the intrinsic energy barriers and suppressing the photo‐corrosion [18,19] . There are many noble‐metals (e. g. Pt, Ru and Pd) and transition‐metals (e. g. Co, Ni and Fe) that have been introduced into the photocatalytic system as redox‐active sites to improve the photocatalytic efficiency [20,21] . Even though in situ photodeposition has been one of the most convenient pathways to load cocatalyst sites, the in situ produced redox‐active metallic species is easily re‐oxidized upon exposed in air and easily leached off during photocatalysis, leading to deactivate the photocatalysts and/or contaminate the reaction mixtures [22–24] …”