Photoelectrocatalytic materials with complexes of two different transition metals as structure-directing agents

Abstract

In recent years, chalcogenides have attracted considerable attention in photoelectrocatalysis. In this study, we report the synthesis of four chalcogenidoarsenates [Ni_0.5Zn_0.5(en)₃]₂As₂S₅ (en = ethylenediamine) (1); [Ni_0.5Zn_0.5(en)₃]₂As₂Se₅ (2); [Ni_0.5Cu_0.5(en)₃]₂As₂Se₅ (3) and [Cu_0.5Zn_0.5(en)₃H₂]As₂Se₇ (4) via a solvothermal method. Notably, each compound incorporates two distinct transition metals within the same complex—a phenomenon that has not been previously reported in arsenic chalcogenides. All four compounds exhibit zero-dimensional (0-D) clustered structures composed of complexes and anions, wherein two different transition metals occupy equivalent positions within the complexes. The photoelectrical properties of compounds 1–4 were systematically investigated, revealing good reproducibility and higher photocurrent densities. We also tested the UV–visible diffuse reflection spectra that the band gaps of 1–4 were 1.67 eV, 1.70 eV, 1.90 eV, and 1.78 eV, respectively, which suggested that these compounds had properties of semiconductor. Additionally, their photocatalytic performance was evaluated, demonstrating good degradation of crystal violet (CV); specifically, compound 2 achieved a photodegradation efficiency of 78.49 % upon irradiation.