An excellent heterojunction nanocomposite solar-energy material for photocatalytic transformation of hydrogen sulfide pollutant to hydrogen fuel and elemental sulfur: A mechanistic insight

Hydrogen sulfide (H2S) is a noxious gas for living organisms and devastating/corrosive agent for metallic structures, which is generated in large scale through natural [geothermal/bacterial] activities or industrial processes, particularly by petroleum and gas industries. Photocatalytic elimination of this plentiful-perilous pollutant and its transformation into hydrogen green fuel and elemental sulfur is a novel/sustainable strategy, which is intriguing from energy and environmental science as well as technological viewpoints. To this end, the design and synthesis of low-price, environmentally friendly, effective photocatalyst/solar-energy materials are highly in demand. Herein, through a facile hydrothermal route, a set of new pn junction xBi(2)S(3)center dot yMnS nanocomposite photocatalysts were synthesized and employed in an alkaline H2S medium (pH = 11) to generate hydrogen fuel and elemental sulfur under atmospheric pressure at room temperature conditions. The maximum conversion yield was attained at the molar ratio x/y = 2, where the photocatalyst exhibited the lowest charge recombination, strong photon absorption, and the greatest surface area among the synthesized nanocomposite materials. Furthermore, it was witnessed that disulfide (S-2(2-)) was the only oxidation product in the reaction medium, which could be effortlessly precipitated as elemental sulfur by acidification of the medium and lowering the pH to about 5. (C) 2019 Elsevier Inc. All rights reserved.