Photoelectrocatalytic self-cross coupling enabling carbon chain elongation

. Moreover, diverse C2-C6 polyol substrates can be elongated to carbon-chain derivatives, demonstrating universal chain-elongation capability. In situ spectroscopy captures the dynamic evolution of reaction intermediates and verifies the critical role of chlorine radicals in enhancing the generation rates of carbon-centered and hydroxyl radicals. This work not only provides a solar-driven cross-coupling mechanism but also pioneers a green chemical synthesis pathway for sustainable and advanced long-chain chemicals.