Synchronous optimization of HO and H adsorption on NiOTe nanodots for alkaline photocatalytic H evolution.

Suitable HO and H adsorption on the surface of transition metal chalcogenide cocatalyst is highly required to achieve their excellent alkaline H-evolution rate. However, the weak adsorption of HO and H atoms on NiTe surface greatly hinders its alkaline H-evolution efficiency. Herein, an electron-deficient modulation strategy is proposed to synchronously improve the adsorption of HO and H atoms on NiTe surface, which can greatly improve the alkaline photocatalytic H evolution of TiO. In this case, highly electronegative oxygen atoms are introduced into the NiTe cocatalysts to induce the formation of electron-deficient Ni and Te sites in the ultra-small-sized NiOTe nanodots (0.5-2 nm), which can be uniformly loaded onto the TiO surface to prepare the NiOTe/TiO photocatalysts by a facile complexation-photodeposition strategy. The resulting NiOTe/TiO (0.6:0.4) photocatalyst exhibits the optimal activity (2143.36 μmol g h), surpassing the activity levels of TiO and NiTe/TiO samples by 42.3 and 1.8 times, respectively. The experimental and theoretical investigations have revealed that the presence of highly electronegative O atoms in the NiOTe cocatalyst can redistribute the charges of Ni and Te atoms for the formation of electron-deficient Ni and Te active sites, thereby synchronously enhancing the adsorption of HO on Ni sites and H on Te sites and promoting alkaline photocatalytic H evolution. The current research about the synchronous optimization of the HO and H adsorption offers a significant approach to design high-performance H-evolution materials.