Control the energy band potential of ZnMgO solid solution with enhanced photocatalytic hydrogen evolution capacity

In this study, we prepared a novel hierarchic nanorod ZnMgO solid solution photocatalyst, and in the crystal, part of Zn atoms were replaced by Mg atoms. Experimental results and theoretical calculation data firstly indicated that the energy band structure of the ZnO can be tuned with the Mg elements doping in it. Especially, during this process, the conduction band (CB) potential of ZnMgO solid solution moved to more negative site gradually with the Mg content increasing, which is an important characteristic for n-type water splitting photocatalyst. When the mole ratio of Mg in the reaction solution reach to 50%, corresponding end-product ZnMgO showed a much more negative CB potential (−0.46 V vs NHE) than pure ZnO (−0.05 V vs NHE), and the photocatalytic for hydrogen evolution product of ZnMgO solid solution increased dramatically than pure ZnO (from near zero of ZnO to 1103.9 μmol/g in 4 h). Furthermore, in the future, based on the ZnMgO solid solution prepared in this study, more visible-light-responsive solid solution with suitable water splitting band structure, such as ZnMgON and ZnMgOS etc., can be expected.