Electrical Charge Polarization Induced by Alternating Temperature Gradient to Promote Z-Scheme Photocatalytic Hydrogen Evolution and Imine Production

Abstract

Here, reported photothermal-pyroelectric-Fe0.9Ni0.1S2/ZnSnO3 photocatalytic system via hydrothermal and annealing methods. Fe0.9Ni0.1S2 nanoparticles (NPs) could convert most of near-infrared (NIR) light energy into heat energy to drive the pyroelectric effect of ZnSnO3, causing natural polarization and thermoelectric effects under the condensed water circulation. As a result, the as-designed Fe0.9Ni0.1S2/ZnSnO3-2 composites could yield up to 7.194 mmol g-1 h-1 with exceptional photocatalytic performance under simulated sunlight. This result was 5.41 and 4.92-fold those of Fe0.9Ni0.1S2 and ZnSnO3, respectively, with 16.66% apparent quantum yield under 365 nm monochromatic light. At the same time, the composites could also oxidize BA and yield up to 6.640 mmol g-1 h-1 n-benzylidene benzylamine with a 90.2% selectivity. Due to the synergistic effect of Z-scheme's built-in electric field and photothermal-pyroelectric of Fe0.9Ni0.1S2/ZnSnO3, the surface charges released on them could direct the charge transfer pathways and restrain their recombination with accelerated electron transfer kinetics, thus extending the carrier lifetime.

Keywords: Bifunctional, Benzylamine coupling oxidation, Charge polarization, Hydrogen production, Temperature gradient