Lingxia Zhang

The electrochemical CO ₂ reduction reaction (CO ₂ RR) using copper‐based catalysts offers a promising pathway for energy recycling. However, controlling product selectivity remains a significant challenge. In this work, we systematically investigate the size‐dependent electrocatalytic performance of cubic Cu ₂ O catalysts. A remarkable switch in product selectivity from C ₂ H ₄ to CH ₄ is observed as the catalyst size increases. Comprehensive characterizations reveal that the larger Cu ₂ O catalyst (Cu ₂ O‐3000) exhibits superior resistance to electroreduction, thereby maintaining a high proportion of surface Cu ⁺ species. These retained Cu ⁺ species suppress C─C coupling and promotes the formation of CH ₄ . In contrast, smaller Cu ₂ O catalysts (Cu ₂ O‐500 and Cu ₂ O‐1000) undergo rapid electroreduction, forming the Cu ⁰ /Cu ⁺ interfaces that facilitate C─C coupling toward C ₂ H ₄ . Furthermore, in situ characterizations indicate that a high density of surface Cu ⁺ species, coupled with a scarcity of Cu ⁰ /Cu ⁺ sites, significantly enhances the adsorption of both OH ⁻ ions and *CO intermediates. This configuration shifts the hydrogenation pathway of *CO from forming *COH toward *CHO intermediates, thereby favoring the formation of CH ₄ over C ₂ H ₄ . Consequently, we establish a distinct structure–performance relationship between the particle size of Cu ₂ O catalysts and the surface content of Cu ⁺ species, thereby providing a viable strategy for regulating product distribution from CO ₂ RR.

Understanding and tailoring catalyst surface species is crucial for controlling reaction pathways and product selectivity. Herein, we demonstrate that triply bridging hydroxyl ( t OH) on ceria oxide surfaces profoundly alter the CO ₂ hydrogenation pathway, shifting the major product from CO to CH ₄ . Steam treatment of CeO ₂ supported rhenium catalyst generates abundant t ‐OH species, leading to a tenfold increase in the CH ₄ formation rate and ∼90% selectivity at 340°C and 30 bar. The operando spectroscopy combined with isotope‐labeling experiments provide direct evidences for the involvement of t ‐OH in CH ₄ formation. Density functional theory calculations reveal that t ‐OH acts as a reactive proton donor, facilitating the hydrogenation of ^* HCOO to ^* HCOOH and thereby suppressing the decomposition of ^* HCOO to CO. Kinetic analysis further indicates that the presence of t ‐OH lowers the apparent activation energy from 118.8 kJ mol ⁻¹ to 73.2 kJ mol ⁻¹ , enabling a more efficient methanation pathway. This phenomenon is also discovered to be universal on other oxide‐supported Ni, Ru, and Rh catalysts. This work highlights the pivotal role of surface hydroxyls in CO ₂ hydrogenation reaction and offers fundamental insights into engineering surface‐species to modulate product selectivity.

Understanding and tailoring catalyst surface species is crucial for controlling reaction pathways and product selectivity. Herein, we demonstrate that triply bridging hydroxyl ( t OH) on ceria oxide surfaces profoundly alter the CO ₂ hydrogenation pathway, shifting the major product from CO to CH ₄ . Steam treatment of CeO ₂ supported rhenium catalyst generates abundant t ‐OH species, leading to a tenfold increase in the CH ₄ formation rate and ∼90% selectivity at 340°C and 30 bar. The operando spectroscopy combined with isotope‐labeling experiments provide direct evidences for the involvement of t ‐OH in CH ₄ formation. Density functional theory calculations reveal that t ‐OH acts as a reactive proton donor, facilitating the hydrogenation of ^* HCOO to ^* HCOOH and thereby suppressing the decomposition of ^* HCOO to CO. Kinetic analysis further indicates that the presence of t ‐OH lowers the apparent activation energy from 118.8 kJ mol ⁻¹ to 73.2 kJ mol ⁻¹ , enabling a more efficient methanation pathway. This phenomenon is also discovered to be universal on other oxide‐supported Ni, Ru, and Rh catalysts. This work highlights the pivotal role of surface hydroxyls in CO ₂ hydrogenation reaction and offers fundamental insights into engineering surface‐species to modulate product selectivity.

Piezocatalysis is a promising chemical synthesis technique, but it is generally restricted to noncentrosymmetric materials, severely limiting catalyst selection. The flexoelectric effect bypasses this symmetry constraint. However, its catalytic contribution is often overlooked, as conventional materials generate only modest strain gradients. Inspired by the hierarchical radial gradients in natural bamboo, we developed radial‐gradient BiO(Cl, Br) nanosheets. This architecture breaks the centrosymmetry of BiOCl to invoke robust piezoelectricity while simultaneously amplifying flexoelectricity through built‐in mechanical heterogeneity. Driven by a triple‐field synergism of built‐in, piezo‐, and flexoelectric fields, the BiO(Cl, Br) nanosheets achieve a high H ₂ O ₂ production rate of 742.2 µmol g ⁻¹ h ⁻¹ , approximately 423% of pristine BiOCl. Theoretical analysis reveals that the mechanical strain and Br doping synergistically modulate the work function and the p ‐band center, facilitating spin‐selective O ₂ orbital coupling and reducing the activation barrier for superoxide formation. This work provides an effective strategy to break through symmetry constraints in piezocatalysis, paving the way for the rational design of high‐performance mechano‐catalysts through gradient engineering.

Photocatalytic co-conversion of CH4 and CO2 for synthesizing C2+ chemicals represents an environmentally friendly strategy for advancing carbon neutrality and reducing the greenhouse effect. However, several critical challenges remain, especially the difficulties in methane activation and heterogeneous coupling between CH4-derived and CO2-derived intermediates. Herein, we report a Cu-incorporated TiO2-SiO2 (Cu-TS) photocatalyst capable of achieving heterogeneous coupling between *CO and *CH3 intermediates, respectively, derived from CO2 and CH4. The optimized system demonstrates a C2 selectivity of 52% and a total C2 hydrocarbon production rate of 18 ± 2 μmol g−1 h−1, comprising 16 ± 1 μmol g−1 h−1 of C2H6 and 2 ± 1 μmol g−1 h−1 of C2H4 under 365 nm irradiation at ambient conditions, which is approximately 6.8 and 34.2 times those on pure TiO2-SiO2 (TS) and on Cu-TiO2, respectively. Mechanistic investigations indicate that CH4 preferentially interacts with ·OH radicals generated from Si-OH groups, forming the key intermediate *CH3 adsorbed on the Ti sites. Cu nanoparticles serve as active sites for CO2 adsorption and reduction to form the *CO intermediate. Subsequently, these two intermediates heterogeneously couple with each other at adjacent Cu and Ti sites to yield C2 hydrocarbons. This study realizes ·OH-mediated CH4 activation on CH4 and CO2 co-conversion and achieves the heterogeneous C−C coupling between *CO and *CH3 intermediates on adjacent dual-metal sites, establishing a strategy for designing multi-site synergistic photocatalysts targeting C2 production under mild conditions.

It remains a significant challenge to electrocatalytically convert CO ₂ into multi‐carbon (C ₂₊ ) products with both high selectivity and industrial‐grade current density. Herein, we report a pH‐directed strategy for growing CuO catalysts with precisely controlled morphologies. Among them, nanorod‐like CuO (R‐CuO) achieves an exceptional performance with a Faradaic Efficiency of 84.0% at 500 mA·cm ⁻² toward C ₂ products. X‐ray photoelectron spectroscopy reveals that during electrochemical CO ₂ reduction reaction (CO ₂ RR), R‐CuO preserves the richest surface Cu ⁺ species (73.8%), thereby furnishing abundant Cu ⁰ /Cu ⁺ interfaces stemming from the unique “fragmentation‐agglomeration” reconstruction process. XAS results disclose a low coordination number (CN = 8.71) for the Cu─Cu scattering path and a high CN (0.72) for the Cu─O path in post‐reaction R‐CuO, underscoring its defective structure and Cu ⁺ retention. In situ characterizations further reveal that the robust Cu ⁰ /Cu⁺ interfaces markedly enhance the adsorption of OH ⁻ and ^* CO intermediate, accelerating the rate‐determining C─C coupling between ^* CO and ^* COH intermediates and driving selective C ₂ formation. Therefore, we have established a relationship between the morphology of CuO and the pivotal Cu ⁰ /Cu ⁺ interfaces, providing a rational strategy for dynamically tailoring interface evolution toward selective C ₂ production from CO ₂ RR.