Aqueous-phase reforming (APR) of biomass-derived effluent is an attractive route to renewable hydrogen, yet real, acid-rich streams reform poorly and rapidly deactivate the commercial catalysts. Herein, we propose a rational catalyst design strategy involving Pt atoms anchored on nitrogen-doped carbon and interfaced with ZnO domains. The developed catalyst (HD-PtN/ZnO/C) features highly dispersed Pt as C-C activation sites; Lewis-acidic ZnO to enhance the inner water-gas shift (WGS) reaction; N-induced locally alkaline microenvironment that facilitates the adsorption and activation of acidic substrates, successfully establishing a synergistic system. The design enables nearly a complete conversion of the mixed aliphatic acids effluent, corresponding to TOFH2 as 5288 h-1, 3.4 times higher than that from the commercial Pt/C catalyst. N-doping not only facilitates an excellent hydrogen yield (61.3 mmolH2 gTOC-1) but also contributes significantly to the stability of Pt and ZnO species. This catalyst represents a breakthrough by simultaneously maintaining high APR activity and catalyst structural stability in a real acidic effluent system. Sustainability tests showed activity can be fully recovered by a mild 300 °C calcination, enabling at least five cycles. This work paves the way for an efficient and durable hydrogen production from acidic industrial wastewater and expands the applications of single-atom catalysts.
Isobutene is an important platform chemical that is still predominantly produced from petroleum-derived feedstocks. The ferulic acid decarboxylase (Fdc) catalyzed decarboxylation of 3-methylcrotonic acid provides a green and sustainable route to bio-based isobutene. However, the poor activity of native Fdc toward this non-natural substrate severely limits its practical application. Here, we developed an integrated enzyme-engineering strategy that combines sequence-cluster mining with distal-site engineering to improve catalytic performance. The engineered triple-site mutant V132C/Y298F/S484A (3MUT) exhibited 5.3-fold the isobutene production of WT. Coupling this mutant with reaction-process optimization and cofactor engineering increased the isobutene yield to 67.9%, representing the highest reported yield to date. Mechanistic studies revealed that distal-site mutations in 3MUT reshaped the active site by disrupting the M293-mediated hydrogen bond that blocks the substrate to active site, then further promoting favorable hydrogen-bond interactions with the substrate via R183 and E292, respectively. These findings establish an efficient route for sustainable bio-based isobutene production and demonstrate the potential of distal-site engineering for improving UbiD-family decarboxylases.
Ting Feng, Xuanyu Cao, Liran Yang et al.· Bioresource Technology· 0 citations
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