 A compact heterojunction consisting of half-metallic C, Cn, 3, HmCn, hydrothermally embedded in Biobr, Biob, as the backbone enhances charge separation in semiconductor photocatalysts for efficient artificial photosynthesis, resulting in a larger electron transfer rate and increased photocatolitic C02 conversion efficiency. This article was authored by Xinhuang Xu, Hengmen Su, Jin Yuan Lu, and others.