Yunxiang Li

Electrocatalysis plays a pivotal role in driving the progress of modern technologies and industrial processes such as energy conversion and emission reduction. Perovskite oxides, an important family of electrocatalysts, have garnered substantial attention in diverse catalytic reactions because of their highly tunable composition and structure, as well as their considerable activity and stability. This review delves into the mechanisms of electrocatalytic reactions that use perovskite oxides as electrocatalysts, while also providing a comprehensive summary of the potential key factors that influence catalytic activity across various reactions. Furthermore, this review offers an overview of advanced characterizations used for studying catalytic mechanisms and proposes approaches to designing highly efficient perovskite oxide electrocatalysts.

Exploring unique single‐atom sites capable of efficiently reducing O₂ to H₂O₂ while being inert to H₂O₂ decomposition under light conditions is significant for H₂O₂ photosynthesis, but it remains challenging. Herein, we report the facile design and fabrication of polymeric carbon nitride (CN) decorated with single‐Zn sites that have tailorable local coordination environments, which is enabled by utilizing different Zn salt anions. Specifically, the O atom from acetate (OAc) anion participates in the coordination of single‐Zn sites on CN, forming asymmetric Zn−N₃O moiety on CN (denoted as CN/Zn−OAc), in contrast to the obtained Zn−N₄ sites when sulfate (SO₄) is adopted (CN/Zn−SO₄). Both experimental and theoretical investigations demonstrate that the Zn−N₃O moiety exhibits higher intrinsic activity for O₂ reduction to H₂O₂ than the Zn−N₄ moiety. This is attributed to the asymmetric N/O coordination, which promotes the adsorption of O₂ and the formation of the key intermediate *OOH on Zn sites due to their modulated electronic structure. Moreover, it is inactive for H₂O₂ decomposition under both dark and light conditions. As a result, the optimized CN/Zn−OAc catalyst exhibits significantly improved photocatalytic H₂O₂ production activity under visible light irradiation.

Exploring unique single‐atom sites capable of efficiently reducing O₂ to H₂O₂ while being inert to H₂O₂ decomposition under light conditions is significant for H₂O₂ photosynthesis, but it remains challenging. Herein, we report the facile design and fabrication of polymeric carbon nitride (CN) decorated with single‐Zn sites that have tailorable local coordination environments, which is enabled by utilizing different Zn salt anions. Specifically, the O atom from acetate (OAc) anion participates in the coordination of single‐Zn sites on CN, forming asymmetric Zn−N₃O moiety on CN (denoted as CN/Zn−OAc), in contrast to the obtained Zn−N₄ sites when sulfate (SO₄) is adopted (CN/Zn−SO₄). Both experimental and theoretical investigations demonstrate that the Zn−N₃O moiety exhibits higher intrinsic activity for O₂ reduction to H₂O₂ than the Zn−N₄ moiety. This is attributed to the asymmetric N/O coordination, which promotes the adsorption of O₂ and the formation of the key intermediate *OOH on Zn sites due to their modulated electronic structure. Moreover, it is inactive for H₂O₂ decomposition under both dark and light conditions. As a result, the optimized CN/Zn−OAc catalyst exhibits significantly improved photocatalytic H₂O₂ production activity under visible light irradiation.

Precise manipulation of the coordination environment of single‐atom catalysts (SACs), particularly the simultaneous engineering of multiple coordination shells, is crucial to maximize their catalytic performance but remains challenging. Herein, we present a general two‐step strategy to fabricate a series of hollow carbon‐based SACs featuring asymmetric Zn−N₂O₂ moieties simultaneously modulated with S atoms in higher coordination shells of Zn centers (n≥2; designated as Zn−N₂O₂−S). Systematic analyses demonstrate that the synergetic effects between the N₂O₂ species in the first coordination shell and the S atoms in higher coordination shells lead to robust discrete Zn sites with the optimal electronic structure for selective O₂ reduction to H₂O₂. Remarkably, the Zn−N₂O₂ moiety with S atoms in the second coordination shell possesses a nearly ideal Gibbs free energy for the key OOH* intermediate, which favors the formation and desorption of OOH* on Zn sites for H₂O₂ generation. Consequently, the Zn−N₂O₂−S SAC exhibits impressive electrochemical H₂O₂ production performance with high selectivity of 96 %. Even at a high current density of 80 mA cm⁻² in the flow cell, it shows a high H₂O₂ production rate of 6.924 mol g_cat⁻¹ h⁻¹ with an average Faradaic efficiency of 93.1 %, and excellent durability over 65 h.

Precise manipulation of the coordination environment of single‐atom catalysts (SACs), particularly the simultaneous engineering of multiple coordination shells, is crucial to maximize their catalytic performance but remains challenging. Herein, we present a general two‐step strategy to fabricate a series of hollow carbon‐based SACs featuring asymmetric Zn−N₂O₂ moieties simultaneously modulated with S atoms in higher coordination shells of Zn centers (n≥2; designated as Zn−N₂O₂−S). Systematic analyses demonstrate that the synergetic effects between the N₂O₂ species in the first coordination shell and the S atoms in higher coordination shells lead to robust discrete Zn sites with the optimal electronic structure for selective O₂ reduction to H₂O₂. Remarkably, the Zn−N₂O₂ moiety with S atoms in the second coordination shell possesses a nearly ideal Gibbs free energy for the key OOH* intermediate, which favors the formation and desorption of OOH* on Zn sites for H₂O₂ generation. Consequently, the Zn−N₂O₂−S SAC exhibits impressive electrochemical H₂O₂ production performance with high selectivity of 96 %. Even at a high current density of 80 mA cm⁻² in the flow cell, it shows a high H₂O₂ production rate of 6.924 mol g_cat⁻¹ h⁻¹ with an average Faradaic efficiency of 93.1 %, and excellent durability over 65 h.

Developing highly efficient catalytic sites for O₂ reduction to H₂O₂, while ensuring the fast injection of energetic electrons into these sites, is crucial for artificial H₂O₂ photosynthesis but remains challenging. Herein, we report a strongly coupled hybrid photocatalyst comprising polymeric carbon nitride (CN) and a two‐dimensional conductive Zn‐containing metal–organic framework (Zn‐MOF) (denoted as CN/Zn‐MOF(lc)/400; lc, low crystallinity; 400, annealing temperature in °C), in which the catalytic capability of Zn‐MOF(lc) for H₂O₂ production is unlocked by the annealing‐induced effects. As revealed by experimental and theoretical calculation results, the Zn sites coordinated to four O (Zn‐O₄) in Zn‐MOF(lc) are thermally activated to a relatively electron‐rich state due to the annealing‐induced local structure shrinkage, which favors the formation of a key *OOH intermediate of 2e⁻ O₂ reduction on these sites. Moreover, the annealing treatment facilitates the photoelectron migration from the CN photocatalyst to the Zn‐MOF(lc) catalytic unit. As a result, the optimized catalyst exhibits dramatically enhanced H₂O₂ production activity and excellent stability under visible light irradiation.

Developing highly efficient catalytic sites for O₂ reduction to H₂O₂, while ensuring the fast injection of energetic electrons into these sites, is crucial for artificial H₂O₂ photosynthesis but remains challenging. Herein, we report a strongly coupled hybrid photocatalyst comprising polymeric carbon nitride (CN) and a two‐dimensional conductive Zn‐containing metal–organic framework (Zn‐MOF) (denoted as CN/Zn‐MOF(lc)/400; lc, low crystallinity; 400, annealing temperature in °C), in which the catalytic capability of Zn‐MOF(lc) for H₂O₂ production is unlocked by the annealing‐induced effects. As revealed by experimental and theoretical calculation results, the Zn sites coordinated to four O (Zn‐O₄) in Zn‐MOF(lc) are thermally activated to a relatively electron‐rich state due to the annealing‐induced local structure shrinkage, which favors the formation of a key *OOH intermediate of 2e⁻ O₂ reduction on these sites. Moreover, the annealing treatment facilitates the photoelectron migration from the CN photocatalyst to the Zn‐MOF(lc) catalytic unit. As a result, the optimized catalyst exhibits dramatically enhanced H₂O₂ production activity and excellent stability under visible light irradiation.

Gas‐liquid‐solid triple‐phase interfaces (TPI) are essential for promoting electrochemical CO₂ reduction, but it remains challenging to maximize their efficiency while integrating other desirable properties conducive to electrocatalysis. Herein, we report the elaborate design and fabrication of a superhydrophobic, conductive, and hierarchical wire membrane in which core–shell CuO nanospheres, carbon nanotubes (CNT), and polytetrafluoroethylene (PTFE) are integrated into a wire structure (designated as CuO/F/C(w); F, PTFE; C, CNT; w, wire) to maximize their respective functions. The realized architecture allows almost all CuO nanospheres to be exposed with effective TPI and good contact to conductive CNT, thus increasing the local CO₂ concentration on the CuO surface and enabling fast electron/mass transfer. As a result, the CuO/F/C(w) membrane attains a Faradaic efficiency of 56.8 % and a partial current density of 68.9 mA cm⁻² for multicarbon products at −1.4 V (versus the reversible hydrogen electrode) in the H‐type cell, far exceeding 10.1 % and 13.4 mA cm⁻² for bare CuO.

Gas‐liquid‐solid triple‐phase interfaces (TPI) are essential for promoting electrochemical CO₂ reduction, but it remains challenging to maximize their efficiency while integrating other desirable properties conducive to electrocatalysis. Herein, we report the elaborate design and fabrication of a superhydrophobic, conductive, and hierarchical wire membrane in which core–shell CuO nanospheres, carbon nanotubes (CNT), and polytetrafluoroethylene (PTFE) are integrated into a wire structure (designated as CuO/F/C(w); F, PTFE; C, CNT; w, wire) to maximize their respective functions. The realized architecture allows almost all CuO nanospheres to be exposed with effective TPI and good contact to conductive CNT, thus increasing the local CO₂ concentration on the CuO surface and enabling fast electron/mass transfer. As a result, the CuO/F/C(w) membrane attains a Faradaic efficiency of 56.8 % and a partial current density of 68.9 mA cm⁻² for multicarbon products at −1.4 V (versus the reversible hydrogen electrode) in the H‐type cell, far exceeding 10.1 % and 13.4 mA cm⁻² for bare CuO.

Single‐atom catalysts (SACs) are being pursued as economical electrocatalysts. However, their low active‐site loading, poor interactions, and unclear catalytic mechanism call for significant advances. Herein, atomically dispersed Ni/Co dual sites anchored on nitrogen‐doped carbon (a‐NiCo/NC) hollow prisms are rationally designed and synthesized. Benefiting from the atomically dispersed dual‐metal sites and their synergistic interactions, the obtained a‐NiCo/NC sample exhibits superior electrocatalytic activity and kinetics towards the oxygen evolution reaction. Moreover, density functional theory calculations indicate that the strong synergistic interactions from heteronuclear paired Ni/Co dual sites lead to the optimization of the electronic structure and the reduced reaction energy barrier. This work provides a promising strategy for the synthesis of high‐efficiency atomically dispersed dual‐site SACs in the field of electrochemical energy storage and conversion.