Rational Band Design in Metal Chalcogenide Ba₆Zn₆HfS₁₄: Splitting Orbitals, Narrowing the Forbidden Gap, and Boosting Photocatalyst Properties

Abstract

The insufficient light sources absorption often limits photocatalyst applications of metal chalcogenides because of their excessively broad band gap. Thus, it is necessary to discover and design a compound with a rational band gap. Here, a new visible-light photocatalyst, Ba6Zn6HfS14, is prepared through a traditional high temperature solid-state reaction. A set of experiments on the visible-light decomposition of methylene blue demonstrated that the photocatalytic efficiency of Ba6Zn6HfS14 (0.00761 min–1) is improved, compared to that of Ba6Zn6ZrS14 (0.00553 min–1), which proved to be a previously reported visible-light photocatalyst with a similar structure. The UV–visible reflection spectra demonstrated that the energy gap of Ba6Zn6HfS14 (E 1 = 1.45 eV; E 2 = 2.55 eV) is smaller than that of Ba6Zn6ZrS14 (E 1 = 1.78 eV; E 2 = 2.50 eV; E 3 = 2.65 eV). The Ba6Zn6HfS14 absorbs more visible light and exhibits preferably photocatalytic activity. The origin of split energy bands was elucidated via the first calculations.

Synthesis, Electrochemistry, Photophysics, and Photochemistry of a Discrete Tetranuclear Copper(I) Sulfido Cluster

“…At the same time, polynuclear d 10 metal complexes have received much attention. − ,− In particular, the chemistry of polynuclear d 10 metal chalcogenide complexes represents a very important division of structural chemistry because of the highly flexible bonding modes of chalcogens. Their intriguing photophysical and luminescence properties have also been largely explored. − ,− Most of the recent works in this area are focused on functional model studies of metal–sulfur redox-active proteins − and the semiconducting − and photocatalytic properties of metal chalcogenides. − Accordingly, an exploration into the photophysical and photochemical properties of discrete coinage metal chalcogenide clusters and aggregates would represent an attractive area of research.…”