Cu-phen Coordination Enabled Selective Electrocatalytic Reduction of CO2 to Methane.

Manipulation of selectivity in the catalytic electrochemical carbon dioxide reduction reaction (eCO2RR) poses significant challenges due to inevitable structure reconstruction. One approach is to develop effective strategies for controlling reaction pathways to gain a deeper understanding of mechanisms in robust CO2RR systems. In this work, by precise introduction of 1,10-phenanthroline as a bidentate ligand modulator, the electronic property of the copper site was effectively regulated, thereby directing selectivity switch. By modification of [Cu3(btec)(OH)2]n, the use of [Cu2(btec)(phen)2]n·(H2O)n achieved the selectivity switch from ethylene (faradaic efficiency (FE) = 41%, FEC2+ = 67%) to methane (FECH4 = 69%). Various in situ spectroscopic characterizations revealed that [Cu2(btec)(phen)2]n·(H2O)n promoted the hydrogenation of *CO intermediates, leading to methane generation instead of dimerization to form C2+ products. Acting as a delocalized π-conjugation scaffold, 1,10-phenanthroline in [Cu2(btec)(phen)2]n·(H2O)n helps stabilize Cuδ+. This work presents a novel approach to regulate the coordination environment of active sites with the aim of selectively modulating the CO2RR.

Boron-Assisted Cobalt-Catalyzed C-H Methylation Using CO2 and H2.

C-H methylation of heteroarenes (e.g., indoles, pyrroles, etc.) is frequently applied in the synthesis of drug/biorelated compounds. We herein report the use of CO2/H2 as a methylation reagent for selective C-H methylation of indoles and pyrroles in the presence of cobalt/B(C6F5)3 cocatalysts. The Lewis acidic additive B(C6F5)3 is essential to achieving good reactivity for a broad scope of substituted indoles and pyrroles (20 examples, up to 92% yields). The C-H methylation is accomplished via the CO2 reduction/C-C bond formation/reduction sequence. Water is the only byproduct. This system based on the use of non-noble metal catalysts features an environmentally benign alternative for C-H methylation.

Facile preparation of BiOBr/cellulose composites by in situ synthesis and its enhanced photocatalytic activity under visible-light.

BiOBr/regenerated cellulose composites photocatalysts were easily prepared by in situ synthesis method with the utilization of pulp board as the cellulose source in TEMPO (2, 2, 6, 6-tetramethylpiperidine-1-oxyl radical)-Mediated Oxidation. The physicochemical characteristic of the BiOBr/cellulose composites are systematically indicated by SEM, XRD, FT-IR, TG, BET, XPS, UV-vis, TOC, HPLC and EIS. The results indicated that the BiOBr nanoparticles were incorporated into cellulose surface, and there was a strong interaction between the hydroxyl groups of regenerated cellulose (RC) and the BiOBr through hydrogen bonding interactions. Under visible light irradiation, the composites showed remarkable photocatalytic activity for degradation of Rhodamine B (C0 = 25 mg L-1) with degradation percentage of 99% within only 50 min irradiation and 88.6% after four recycles. This study promotes that the BiOBr/cellulose composites can act as a new and green portable photocatalyst in the field of wastewater treatment.