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Direct photochemical carboxylation of C(sp3)–H bonds with CO2 is an uphill task and it has attracted increasing attention. In the present study, we report an elegant strategy for visible-light-triggered C(sp3)-H carboxylation of amines with CO2 into α-amino acids using a stable crystalline polyimide-based covalent organic framework (PI-COF) as an efficient heterogeneous photocatalyst and NiO nanoparticles (NiO NPs) as a cocatalyst under ambient conditions (room temperature and atmospheric CO2 pressure). Diverse amino acids are produced in moderate-to-high yields. This methodology tolerates a range of functional groups and displays remarkable regioselectivity. Various drugs were effectively achieved using this light-assisted approach. The high chemical stability of the COF and its strong interactions with NiO NPs renders the catalytic system to be highly recyclable (i.e., over five times). More interestingly, this photoinduced carboxylation reaction occurred without the involvement of any sacrificial electron donors. Based on computational (DFT) investigations, a tentative mechanism revealed the formation of CO2 radical anion at the conduction band (CB) of the COF via single electron transfer mediated by NiO nanoparticles which combined with amine radical cation at the valence band of the COF to form α-amino acid.

Electrocatalytic hydrogen (H2) generation became a prime research topic in the last decade since H2 is a clean source of energy and combustion as it does not produce CO2. Conventional electrolysis is associated with the formation of oxygen via the oxygen evolution reaction (OER) at the anode. This kinetically sluggish multistep four-electron transfer OER process needs additional energy to split water. Substitution of the OER process by the easily oxidizable substrate oxidation reaction could be a lucrative way to get H2 at a much lower potential budget than the conventional one. Biomass-derived chemicals like bioalcohols (methanol, ethanol, glycerol (GlyOH), butanol, 5-hydroxymethylfurfural (HMF) obtained from hydrolysis or fermentation of biomass) could be easily oxidized to value-added commodity chemicals like formic acid, acetic acid, propionic acid, acetone, and 2,5-furandicarboxylic acid (FDCA) at the anode part of the electrolyzer. Thermodynamically, the bond dissociation energy of “C–H” and “O–H” bonds of these organic substrates is much lower than the “O–H” bond dissociation energy of water. So, to make the overall substrate oxidation reaction kinetically more feasible, an efficient electrocatalyst needs to be developed. Herein, we present a noble metal-free Ni1–x Co x Se electrocatalyst for efficient and selective conversion of alcohol molecules to value-added commodity chemicals. Particularly, Ni0.9Co0.1Se composition showed the best substrate oxidation activity compared to pristine NiSe, CoSe, and other state-of-the-art catalysts. The substrate scope is verified with methanol, ethanol, isopropanol, ethylene glycol (EGOH), GlyOH, and malic acid. Both experimental and theoretical understanding (DFT) established the fact that Co doping manipulates the NiII → NiIII OOH redox chemistry and accelerates the formation of active hypervalent Ni(Co)OOH species at a lower potential budget than NiOOH. For all catalyses, Ni0.9Co0.1Se shows superior activity with 80–100% product conversion along with a Faradaic yield of 80–95%.