Hengming Huang

Photocatalytic CO ₂ reduction to multi-carbon products like ethanol remains challenging. We report a porous liquid (PL) system, PL(Cu-Cu ₂ O@NU), driving selective CO ₂ -to-ethanol conversion. It features Cu ⁰ /Cu ⁺ dual sites in NH ₂ -UiO-66 (NU) hybridized with a methoxypolyethylene glycol-functionalized imidazolium ionic liquid (IL). This system facilitates C-C coupling via a triple enrichment mechanism: IL and NU synergistically enrich CO ₂ , IL enriches electrons at Cu sites, and confined pores enrich intermediates. Consequently, PL(Cu-Cu ₂ O@NU) achieves an 83.3 μmol·g ⁻¹ ·h ⁻¹ ethanol yield with 95.2% selectivity, outperforming Cu-Cu ₂ O@NU by 4.7-fold. Control experiments (showing no ethanol over isolated NU, IL, or Cu-Cu ₂ O) directly validate this mechanism. Supplemental computations substantiate these findings: molecular dynamics confirm confined pores reduce *CO diffusion for enrichment, while density functional theory reveals lowered C-C coupling barriers. Furthermore, d-band upshifts enhance CO ₂ -Cu overlap, and Cu ⁰ /Cu ⁺ sites mediate the critical *CO → *COCO transition. These integrated observations firmly establish PLs as robust confinement-driven platforms for selective CO ₂ -to-C ₂ ⁺ conversion.

Methylamine hydrochlorides (MACls) are important building blocks in organic synthesis, yet their conventional production requires energy-intensive, multistep processes. Herein, we report a photocatalytic strategy for the direct synthesis of MACls from methanol and ammonium chloride under mild conditions. A high MACls yield of 29.62 mmol·g^-1 is achieved within 4 h over Pd-decorated TiO₂ with oxygen vacancies, outperforming most previously reported photocatalytic C-N coupling systems. In situ spectroscopy, isotope effects, and theoretical studies reveal that methanol is initially oxidized to formaldehyde, a key intermediate that reacts with ammonium chloride via nucleophilic condensation and successive methylation to form C-N bonds, thereby yielding MACls. Photoexcitation enables both the thermodynamically and kinetically unfavorable methanol-to-formaldehyde conversion and drives stepwise methylation reactions, which are otherwise inactive in the dark. The cooperative interaction between Pd and oxygen vacancies promotes charge separation and methanol dehydrogenation, resulting in highly efficient MACls photosynthesis. This work advances mechanistic insights into photocatalytic C-N bond formation and presents a sustainable approach for producing value-added C-N compounds from simple C₁ and nitrogen feedstocks.

Gradient Mn-doping in CdS forms reverse quantum wells and surface active sites, which enhance charge extraction and O ₂ activation. This achieves a H ₂ O ₂ production rate of 1874 μmol g ⁻¹ h ⁻¹  and an apparent quantum efficiency of 65.2% at 475 nm.

The direct photocatalytic oxidation of methane to value-added chemicals has garnered considerable interest in recent years. However, achieving high productivity while maintaining high selectivity at an appreciable methane conversion rate remains a formidable challenge. Here, we present photochemically-triggered and photothermally-enhanced oxidative coupling of methane to multi-carbon C₂₊ alkanes over an Au and CeO₂ nanoparticle-decorated ZnO photocatalyst, which exhibits a record-breaking C₂₊ production rate of 17,260 μmol g⁻¹ h⁻¹ with ~90% C₂₊ selectivity under wide-spectrum light irradiation without a secondary source of heating. Comprehensive characterizations and computational studies reveal that CH₄ activation is a photochemical reaction initiated by ultraviolet light-excited ZnO, and the introduction of CeO₂ substantially enhances the activation of CH₄ and O₂ due to the cooperative interaction between Au and CeO₂. Concurrently, Au nanoparticles capture visible and near-infrared light to generate localized heating, which greatly promotes the subsequent desorption of produced methyl radical for C–C coupling prior to undergoing further undesired overoxidation.