Sulfur-engineered rhenium single-atoms on borides for tunable syngas and lactic acid co-production

The simultaneous and selective production of syngas and value-added chemicals from biomass-derived feedstocks is fundamentally restricted by sluggish multi-electron-proton transfer and the lack of precisely defined active sites capable of stabilizing reactive intermediates. Here, we report a sulfur-mediated coordination reconstruction strategy that transforms metastable rhenium species on two-dimensional chromium boride into uniformly dispersed Re-S₄ single atoms. The electronic environment of Re-S₄ optimizes the d-band center, stabilizing the key intermediate glyceraldehyde for selective C-C bond cleavage. In this work, the synergistic combination of atomic-scale engineering and reactant kinetics modulation yields a total syngas rate of 34.08 mmol g^-1 h^-1 with a wide-ranging tunable H₂/CO ratio (0.1 to 14.4), alongside a lactic acid yield of 90.8%. The system's robustness is further validated via large-scale outdoor sunlight-tracking tests, demonstrating its potential as a scalable, sustainable biorefinery technology for the concurrent production of gas-phase fuels and liquid-phase platform chemicals.