A noble-metal-free Z-scheme system was constructed for photocatalytic overall splitting.

Bandgap-tunable black phosphorus quantum dots prepared by a liquid exfoliation method in a mixture solvent of N-methylpyrrolidone and oleic acid can act as efficient photocatalysts for the degradation of rhodamine B. This is the first report on solely black phosphorus capable of destroying organic pollutants under visible light irradiation.

This work describes a high-yield extracellular biosynthesis of ZnS QDs via a unique molecular mediation mechanism driven by the mixed sulfate reducing bacteria (SRB). The mixed SRB have obtained the highest ever ZnS QD biosynthesis rate of 35.0–45.0 g/(L·month). The biogenic ZnS QDs with an average crystallite size (ACS) of 6.5 nm have greater PL activity and better uniformity than that of a chemical route. Peculiar extracellular proteins (EPs) with molecular weights of approximately 65 and 14 kDa specially adhere to the ZnS QDs, which cover extraordinarily high contents of acidic amino acids (14.0 mol % Glu and 13.0 mol % Asp) and of nonpolar amino acids (12.0 mol % Ala, 11.0 mol % Gly, and 7.0 mol % Phe), for novel molecular mediation. The vast amount of negative charges in Glu and Asp guides the strong absorption between the EPs and Zn2+ via electrostatic attraction to reach a maximum absorption capacity of 745.9 mg/g within 2.0 h, motivating large and rapid nucleation as the first step of biosynthesis. Meanwhile, bridging and interlinkage occur inside the EPs or between the EPs via hydrophobic interactions dominated by the nonpolar amino acids, resulting in the formation of massive microcavities to control and restrict the growth of ZnS QDs as a template. The novel molecular mediation mechanism triggered by the peculiar EPs with an extraordinary amino acid composition and structure accounts for the high-yield biosynthesis of ZnS QDs. The mixed SRB have also successfully fabricated other metal sulfide QDs, including PbS, CuS, and CdS, through the novel molecular mediation.