Low-energy consumption in the photovoltaic electrocatalytic desulfurization of hydrogen sulfide

Hydrogen sulfide (H2S) is a highly corrosive and toxic gas that causes severe harm to human health and the environment, where effective treatment and removal are viewed as a high priority in sustainable development. The conventional Klaus process facilitates H2S recycling in the form of sulfur but does not effectively generate hydrogen as a valuable target resource. In contrast, electrocatalytic H2S decomposition enables a clean conversion of H2S into hydrogen and sulfur. Sustainable development is a global necessity, emphasizing environmentally conscious approaches to energy production and utilization, notably in the fields of solar and hydrogen energy technologies. China is taking the lead in developing clean energy with a large-scale and rapid expansion of new energy power generation (green electricity). Due to the volatility and indirect characteristics of new energy, it is necessary to support energy storage technology or develop green electricity efficient absorption and conversion technology, further advances require novel and effective means of energy storage, enabling viable green electricity generation, absorption and conversion. The use of renewable energy to promote clean H2S decomposition is significant in a holistic approach to the consumption and utilization of renewable energy directed at the treatment of a recalcitrant pollutant. This represents a significant advancement in state-of-the-art energy systems. The theoretical voltage output associated with the direct electrocatalytic decomposition of H2S is 0.35 V. The process is simple to operate with a high hydrogen production efficiency. The photovoltaic electrocatalytic H2S decomposition is recognized as an environmentally friendly and feasible means of hydrogen production with a low associated energy consumption.In this study, we propose a photovoltaic coupling of electrocatalytic H2S decomposition with solar energy resources to promote a clean and high-value conversion and utilization of H2S gas. We have designed a novel catalyst (Ni3S2/NF) based on an in situ formation of a double-layered nanosheet that is grown on a nickel foam substrate. The Ni3S2/NF has delivered superior catalytic activity concerning the oxygen reduction reaction (SOR) and the hydrogen evolution reaction (HER). In terms of efficiency, a potential of 0.56V vs. RHE (reversible hydrogen electrode) and –0.34V vs. RHE is required to drive a current density of 100 mA cm−2 for the SOR and HER, respectively, which exhibit stable operation for more than 200 h. A photovoltaic electrocatalytic H2S direct decomposition system has been constructed where the energy consumption associated with H2 production is 1.89 kWh/Nm3 H2, representing low energy demands in a novel clean H2 production methodology. The proposed system utilizes self-packaged monocrystalline silicon photovoltaic cell modules to provide the requisite electricity. The design and operation involve an efficient diaphragm electrolysis device, where the Ni3S2/NF electrocatalytic material serves as both the anode and the cathode. A continuous electrolytic hydrogen production is demonstrated, conducted under light irradiation at an intensity of 100 mW cm−2. Stable operation is achieved for more than 10 h with an associated hydrogen production of 1 L d–1. This level of output represents an average Faraday hydrogen efficiency of 99.9%, with an average solar-to-hydrogen (STH) conversion efficiency of up to 6.6%. The results have demonstrated a viable direct electrolysis of H2S to produce high value hydrogen and sulfur chemical products by photovoltaic power generation. The findings of this research offer a novel approach to effective green hydrogen production that achieves efficient conversion of renewable solar energy resources with the targeted production of a new source of energy.