Photocatalytic Coproduction of Diesel Fuel Precursors and H₂ Promoted by [HSO₄⁻] and Water

Photocatalytic CC coupling of 2,5-dimethylfuran (DMF) derived from processing lignocellulosic biomasses coproduces drop-in fuels and green hydrogen with a low-carbon footprint. However, the high reaction barrier for CH bond breaking and uphill overall reaction lead to the slow kinetics of DMF coupling. Here, we reveal that [HSO₄ ^-] and water can collaboratively promote the rate-limiting step of the CH bond breaking on the Ru-ZnIn₂S₄ catalyst. An in-depth study suggests that water mediates hole transfer to the CH bond while [HSO₄ ^-] facilitates electron extraction, thus promoting electron and proton transfer on the Ru-ZnIn₂S₄ surface. Consequently, photocatalytic DMF coupling over Ru-ZnIn₂S₄ produces diesel fuel precursors (DFPs) and H₂ with benchmarking formation rates of 1.5 g g_catal. ^-1 h^-1 and 9.7 mmol g_catal. ^-1 h^-1, respectively. Moreover, the selectivity of branched-chain DFPs reaches 55%. This work puts forward new insight and strategy for photocatalytic CC coupling for the synthesis of biofuels.