Twist engineering induced spin-orbit coupling for photosynthesis of ethane from carbon dioxide and water.

Harnessing sunlight, carbon dioxide, and water to produce two-carbon products is promising but constrained by sluggish kinetics and high carbon-carbon coupling barriers. Here, we report Ni single-atom anchored twisted SnS2 (Ni-TSnS2) for ethane (C2H6) photosynthesis. In-situ electron paramagnetic resonance was developed to observe spin-orbit coupling in Ni-TSnS2. Spontaneous long-range spin-momentum locking originated from spin-orbit coupling enables magnetic-field-free long-range spin pinning. Topological protection inherent to long-range spin-momentum locking enhances its stability and ensures spin-polarized electron supply for charge separation. In-situ electron paramagnetic resonance further revealed single-electron transfer at Ni sites during CO2 reduction. Single-electron transfer raised from spin-orbit coupling induces surface-adsorbed methyl intermediate to form methyl radicals (·CH3). ·CH3-to-C2H6 chain reaction pathway enhances C2H6 photosynthesis and selectivity. Consequently, Ni-TSnS2 achieves a C2H6 production rate of 139.58 ±  5.14 μmol g-1 h-1 with 89.41 ±  4.43% electron selectivity. In this work, we propose a twist engineering strategy to modulate spin states of charge, thereby promoting charge separation and single-electron transfer in photoreduction of CO2 to C2H6.