Fig. 1: Schematic illustration for the approach to solar-driven methanogenesis with M. b-NiCu@CdS.

In other words, the produced protons (H⁺) and photoexcited electrons (e⁻) with CdS under light illumination can transfer to the NiCu alloy, and then be harvested by M. b for efficient CO₂-to-CH₄ conversion via turning down the H₂ production.