Photocatalytic\nConversion of Biomass and Nitrate into\nGlycine

Biomass is a renewable carbon source\nthat comes from\nplants, containing\nchemical energy from the sun. Nitrate, which is a N-containing feedstock\nwith a lower dissociation energy, has a rich distribution in wastewater.\nRenewable biomass and nitrate waste can be converted into valuable\nC–N products through photocatalytic processes, which is becoming\npromising but challenging in the production of different kinds of\nchemicals and fuels. Herein, we report the photoconversion of biomass\nand nitrate into glycine with a 765 μmol g<sub>cat</sub><sup>–1</sup> h<sup>–1</sup> production rate and 15.3% yield\nover a Ba<sup>2+</sup>-modified TiO<sub>2</sub> catalyst. The process\ncascades multiple reactions containing the photoreforming of biomass\nto glycol, nitrate reduction to NH<sub>3</sub>, and finally, C–N\ncoupling to glycine, among which nitrate ions play a dominant role\nin the selective cleavage and oxidation of biomass. Surprisingly,\nafter hydrolysis pretreatment, biopolyols or sugars and even raw wood\nsawdust could react with nitrate to generate glycine. This study provides\nan effective catalytic system to produce glycine from renewable biomass\nand nitrate waste under mild conditions.