Highly efficient twinned MnxCd1-xS homojunction photocatalyst modified by noble metal-free Ni12P5 for H2 evolution under visible light

A series of twin-phase MnxCd1-xS solid solutions with zinc blende (ZB) and wurtzite (WZ) structures were prepared by an alkaline hydrothermal method in this work. When using 0.35 M Na2SO3/0.25 M Na2S solution as a sacrificial agent under visible light (l & GE; 420 nm), the H2 production activity of T-Mn0.5Cd0.5S is 33.4 mmol h-1 g-1, significantly higher than that of ZB-Mn0.5Cd0.5S (15.4 mmol h-1 g-1) or WZ-Mn0.5Cd0.5S (18.2 mmol h-1 g-1). The photocatalytic activity of T-Mn0.5Cd0.5S is further enhanced by introducing Ni12P5 as a cocatalyst, in which the H2 evolution rate of 0.2% Ni12P5/T-Mn0.5Cd0.5S can reach 96.5 mmol h-1 g-1, 2.89 and 1.77 times than that of pure T-Mn0.5Cd0.5S and 0.5% Pt/T-Mn0.5Cd0.5S (54.6 mmol h-1 g-1), respectively. The crystalline phase, microstructure, elemental composition, optical and optoelectronic properties of the samples were char-acterized by XRD, SEM, TEM, HRTEM, XPS, UV-vis, PL and electrochemical workstation. The results show that the formation of a homojunction with interlaced energy band