Titania-Supported Ni₂ P/Ni Catalysts for Selective Solar-Driven CO Hydrogenation.

Abstract

Solar-driven Fischer-Tropsch synthesis (FTS) holds great potential for the sustainable production of fuels from syngas and solar energy. However, the selectivity toward multi-carbon products (C₂₊ ) is often hampered by the difficulty in the regulation of transition metals acting as both light absorption units and active sites. Herein, a partial phosphidation strategy to prepare titania supported Ni₂ P/Ni catalysts for photothermal FTS is demonstrated. Under Xenon lamp or concentrated sunlight irradiation, the optimized catalyst shows a C₂₊ selectivity of 70% at a CO conversion of >20%. Conversely, nickel metal in the absence of Ni₂ P delivers negligible C₂₊ products (≈1%) with methane being the major product (>90%). Structural characterization and density functional theory calculation reveal that the partial phosphidation allows exposed metallic Ni to be active for CO adsorption and activation, while the existence of Ni₂ P/Ni interface is responsible to inhibit CO methanation and promote C-C coupling of adsorbed *CH intermediates. This work introduces a novel phosphidation strategy for nickel-based photothermal catalysts in efficiently harnessing solar energy, and regulating the reaction pathways for CO hydrogenation to deliver high value products.