Novel Bi-based photocatalysts with unprecedented visible light-driven hydrogen production rate: Experimental and DFT insights

Abstract

Green and efficient energy technologies are a key point where nanoscience could make a difference in the paradigm shift from fossil fuels to renewable sources. One attractive possibility is the utilization of solar energy to obtain electricity or chemical fuel based on the ability of semiconductor nanomaterials to function as photocatalysts promoting various oxidation and reduction reactions under sunlight. We report on a novel class of Bi-based photocatalysts for hydrogen production via water splitting. A screening DFT investigation was performed on the Bi2(MO4)3 (M = Cr, Mo, and W) systems. The Bi2(CrO4)3 system exhibits the smallest band gap energy, the highest dielectric constant, and the highest absorption in visible region among the other counterpart materials. Consequently, Bi2(CrO4)3 nanoparticles were synthesized via a simple one-pot method at room temperature and characterized by XRD, XPS, DRS, FE-SEM, HR-TEM, and Raman spectroscopy. The as-prepared yellow Bi2(CrO4)3 nanoparticles exhibited a direct band gap energy of 2.45 eV. The photoactivity of the as-prepared Bi2(CrO4)3 nanoparticles was tested toward the photocatalytic hydrogen production, where reasonable rates of 522.44, 174.15, and 88.24 μmol/g/h were achieved under UV, AM 1.5, and visible irradiations, respectively in the absence of any hole scavengers. Those rates are higher than those reported for Bi-based photocatalysts.