Bandgap Funneling in Bismuth-Based Hybrid Perovskite Photocatalyst with Efficient Visible-Light-Driven Hydrogen Evolution

Abstract

<p>The photocatalytic system using hydrohalic acid (HX) for hydrogen production is a promising strategy to generate clean and renewable fuels as well as value-added chemicals (such as X-2/X-3(-)). However, it is still challenging to develop a visible-light active and strong-acid resistive photocatalyst. Hybrid perovskites have been recognized as a potential photocatalyst for photovoltaic HX splitting. Herein, a novel environmentally friendly mixed halide perovskite MA(3)Bi(2)Cl(9-x)I(x) with a bandgap funnel structure is developed, i.e., confirmed by energy dispersive X-ray analysis and density functional theory calculations. Due to gradient neutral formation energy within iodine-doped MA(3)Bi(2)Cl(9), the concentration of iodide element decreases from the surface to the interior across the MA(3)Bi(2)Cl(9-x)I(x) perovskite. Because of the aligned energy levels of iodide/chloride-mixed MA(3)Bi(2)Cl(9-x)I(x), a graded bandgap funnel structure is therefore formed, leading to the promotion of photoinduced charge transfer from the interior to the surface for efficient photocatalytic redox reaction. As a result, the hydrogen generation rate of the optimized MA(3)Bi(2)Cl(9-x)I(x) is enhanced up to approximate to 341 +/- 61.7 mu mol h(-1) with a Pt co-catalyst under visible light irradiation.</p>