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Electrocatalytic carbonylation of CO and CH 3 OH to dimethyl carbonate (DMC) on metallic palladium (Pd) electrode offers a promising strategy for C1 valorization at the anode. However, its broader application is limited by the high working potential and the low DMC selectivity accompanied with severe methanol self-oxidation. Herein, our theoretical analysis of the intermediate adsorption interactions on both Pd 0 and Pd 4+ surfaces revealed that inevitable reconstruction of Pd surface under strongly oxidative potential diminishes its CO adsorption capacity, thus damaging the DMC formation. Further theoretical modeling indicates that doping Pd with Cu not only stabilizes low-valence Pd in oxidative environments but also lowers the overall energy barrier for DMC formation. Guided by this insight, we developed a facile two-step thermal shock method to prepare PdCu alloy electrocatalysts for DMC. Remarkably, the predicted Pd 3 Cu demonstrated the highest DMC selectivity among existing Pd-based electrocatalysts, reaching a peaked DMC selectivity of 93 % at 1.0 V versus Ag/AgCl electrode. (Quasi) in situ spectra investigations further confirmed the predicted dual role of Cu dopant in promoting Pd-catalyzed DMC formation., (© 2024 Wiley-VCH GmbH.)

Designing high efficiency platinum (Pt)-based catalysts for methanol oxidation reaction (MOR) with high "non-CO" pathway selectivity is strongly desired and remains a grand challenge. Herein, PtRuNiCoFeGaPbW HEA ultrathin nanowires (HEA-8 UNWs) are synthesized, featuring unique cascaded p-d orbital hybridization interaction by inducing dual p-block metals (Ga and Pb). In comparison with Pt/C, HEA-8 UNWs exhibit 15.0- and 4.2-times promotion of specific and mass activity for MOR. More importantly, electrochemical in situ FITR spectroscopy reveals that the production/adsorption of CO (CO * ) intermediate is effectively avoided on HEA-8 UNWs, leading to the complete "non-CO" pathway for MOR. Theoretical calculations demonstrate the optimized electronic structure of HEA-8 UNWs can facilitates a lower energy barrier for the "non-CO" pathway in the MOR., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

Direct borohydride fuel cells (DBFCs) convert borohydride (NaBH 4 ) chemical energy into clean electricity. However, catalytic active site deactivation in NaBH 4 solution limits their performance and stability. We propose a strategy to regulate active sites in Co-based catalysts using polypyrrole modification (Co-PX catalyst) to enhance electrochemical borohydride oxidation reaction (eBOR). As an anode catalyst, the synthesized Co-PX catalyst exhibits excellent eBOR performance in DBFCs, with current density of 280 mA ⋅ cm -2 and power density of 151 mW ⋅ cm -2 , nearly twice that of the unmodified catalyst. The Co-PX catalyst shows no degradation after 120-hour operation, unlike the rapidly degrading control. In-situ electrochemical attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIRS) and density functional theory (DFT) suggest that polypyrrole-modified carbon support regulate the charge distribution, increasing oxidation state and optimizing adsorption/desorption of intermediates. A possible reaction pathway is proposed. This work presents a promising strategy for efficient polymer-modulated catalysts in advanced DBFCs., (© 2023 Wiley‐VCH GmbH.)

Direct ethanol fuel cells hold great promise as a power source. However, their commercialization is limited by anode catalysts with insufficient selectivity toward a complete oxidation of ethanol for a high energy density, as well as sluggish catalytic kinetics and low stability. To optimize the catalytic performance, rationally tuning surface structure or interface structure is highly desired. Herein, a facile route is reported to the synthesis of Rh nanosheets-supported tetrahedral Rh nanocrystals (Rh THs/NSs), which possess self-supporting homogeneous interface between Rh tetrahedrons and Rh nanosheets. Due to full leverage of the structural advantages within the given structure and construction of interfaces, the Rh THs/NSs can serve as highly active electro-catalysts with excellent mass activity and selectivity toward ethanol electro-oxidation. The in situ Fourier transform infrared reflection spectroscopy showed the Rh THs/NSs exhibit the highest C1 pathway selectivity of 23.2%, far exceeding that of Rh nanotetrahedra and Rh nanosheets. Density function theory calculations further demonstrated that self-interface between Rh nanosheets and tetrahedra is beneficial for C-C bond cleavage of ethanol. Meanwhile, the self-supporting of 2D nanosheets greatly enhance the stability of tetrahedra, which improves the catalytic stability., (© 2023 Wiley-VCH GmbH.)

Electrocatalytic nitrogen oxidation reaction (NOR) offers an efficient and sustainable approach for conversion of widespread nitrogen (N 2 ) into high-value-added nitrate (NO 3 - ) under mild conditions, representing a promising alternative to the traditional approach that involves harsh Haber-Bosch and Ostwald oxidation processes. Unfortunately, due to the weak absorption/activation of N 2 and the competitive oxygen evolution reaction, the kinetics of NOR process is extremely sluggish accompanied with low Faradaic efficiencies and NO 3 - yield rates. In this work, an oxygen-vacancy-enriched perovskite oxide with nonstoichiometric ratio of strontium and ruthenium (denoted as Sr 0.9 RuO 3 ) was synthesized and explored as NOR electrocatalyst, which can exhibit a high Faradaic efficiency (38.6 %) with a high NO 3 - yield rate (17.9 μmol mg -1  h -1 ). The experimental results show that the amount of oxygen vacancies in Sr 0.9 RuO 3 is greatly higher than that of SrRuO 3 , following the same trend as their NOR performance. Theoretical simulations unravel that the presence of oxygen vacancies in the Sr 0.9 RuO 3 can render a decreased thermodynamic barrier toward the oxidation of *N 2 to *N 2 OH at the rate-determining step, leading to its enhanced NOR performance., (© 2023 Wiley-VCH GmbH.)

Urea oxidation reaction (UOR) is an ideal replacement of the conventional anodic oxygen evolution reaction (OER) for efficient hydrogen production due to the favorable thermodynamics. However, the UOR activity is severely limited by the high oxidation potential of Ni-based catalysts to form Ni 3+ , which is considered as the active site for UOR. Herein, by using in situ cryoTEM, cryo-electron tomography, and in situ Raman, combined with theoretical calculations, a multistep dissolution process of nickel molybdate hydrate is reported, whereby NiMoO 4 ·xH 2 O nanosheets exfoliate from the bulk NiMoO 4 ·H 2 O nanorods due to the dissolution of Mo species and crystalline water, and further dissolution results in superthin and amorphous nickel (II) hydroxide (ANH) flocculus catalyst. Owing to the superthin and amorphous structure, the ANH catalyst can be oxidized to NiOOH at a much lower potential than conventional Ni(OH) 2 and finally exhibits more than an order of magnitude higher current density (640 mA cm -2 ), 30 times higher mass activity, 27 times higher TOF than those of Ni(OH) 2 catalyst. The multistep dissolution mechanism provides an effective methodology for the preparation of highly active amorphous catalysts., (© 2023 Wiley-VCH GmbH.)

Electroreduction of nitrate into ammonia (NRA) provides a sustainable route to convert the widespread nitrate pollutants into high-value-added products under ambient conditions, which unfortunately suffers from unsatisfactory selectivity due to the competitive hydrogen evolution reaction (HER). Previous strategies of modifying the metal sites of catalysts often met a dilemma for simultaneously promoting activity and selectivity toward NRA. Here, a general strategy is reported to enable an efficient and selective NRA process through coordination modulation of single-atom catalysts to tailor the local proton concentration at the catalyst surface. By contrast, two analogous Ni-single-atom enriched conjugated coordination polymers (NiO 4 -CCP and NiN 4 -CCP) with different coordination motifs are investigated for the proof-of-concept study. The NiO 4 -CCP catalyst exhibits an ammonia yield rate as high as 1.83 mmol h -1 mg -1 with a Faradaic efficiency of 94.7% under a current density of 125 mA cm -2 , outperforming the NiN 4 -CCP catalyst. These experimental and theoretical studies both suggest that the strategy of coordination modulation can not only accelerate the NRA by adjusting the adsorption energies of NRA intermediates on the metal sites but also inhibit the HER through regulating the proton migration with contributions from the metal-hydrated cations adsorbed at the catalyst surface, thus achieving simultaneous enhancement of NRA selectivity and activity., (© 2023 Wiley-VCH GmbH.)

Advanced electrocatalysts for complete oxidation of ethylene glycol (EG) in direct EG fuel cells are strongly desired owing to the higher energy efficiency. Herein, Pd-PdSe heterostructural nanosheets (Pd-PdSe HNSs) have been successfully fabricated via a one-step approach. These Pd-PdSe HNSs feature unique electronic and geometrical structures, in which unconventional p-d hybridization interactions and tensile strain effect co-exist. Compared with commercial Pd/C and Pd NSs catalysts, Pd-PdSe HNSs display 5.5 (6.6) and 2.5 (2.6) fold enhancement of specific (mass) activity for the EG oxidation reaction (EGOR). Especially, the optimum C1 pathway selectivity of Pd-PdSe HNSs reaches 44.3 %, illustrating the superior C-C bond cleavage ability. Electrochemical in situ FTIR spectroscopy and theoretical calculations demonstrate that the extraordinary p-d hybridization interaction and tensile strain effect could effectively reduce the activation energy of C-C bond breaking and accelerate CO* oxidation, boosting the complete oxidation of EG and improving the catalytic performance., (© 2022 Wiley-VCH GmbH.)

Constructing monodispersed metal sites in heterocatalysis is an efficient strategy to boost their catalytic performance. Herein, a new strategy using monodispersed metal sites to tailor Pt-based nanocatalysts is addressed by engineering unconventional p-d orbital hybridization. Thus, monodispersed Ga on Pt 3 Mn nanocrystals (Ga-O-Pt 3 Mn) with high-indexed facets was constructed for the first time to drive ethanol electrooxidation reaction (EOR). Strikingly, the Ga-O-Pt 3 Mn nanocatalyst shows an enhanced EOR performance with achieving 8.41 times of specific activity than that of Pt/C. The electrochemical in situ Fourier transform infrared spectroscopy results and theoretical calculations disclose that the Ga-O-Pt 3 Mn nanocatalyst featuring an unconventional p-d orbital hybridization not only promote the C-C bond-breaking and rapid oxidation of -OH of ethanol, but also inhibit the generation of poisonous CO intermediate species. This work discloses a promising strategy to construct a novel nanocatalysts tailored by monodispersed metal site as efficient fuel cell catalysts., (© 2022 Wiley-VCH GmbH.)

The advancement of efficient electrocatalysts toward the nitrogen reduction reaction (NRR) is critical in sustainable ammonia synthesis under ambient pressure and temperature. Manipulating the electronic configuration of electrocatalysts is particularly vital to form metal-nitrogen (MN) bonds during the NRR through regulating the active electronic states of sites. Here, in sharp contrast to stable 2H MoS 2 without metal chains, MoMo bonding in metastable polymorphs of MoS 2 bulk (zigzag chain in the 1T' phase and diamond chain in the 1T″' phase) is discovered to significantly increase intrinsic electron localization around the metal chains. This can enhance the charge transfer from the adsorbed nitrogen molecule to the metal chains, allowing for boosted NRR kinetics. The electrochemical experiments show that the NH 3 yield rate and the faradaic efficiency of the metastable 1T″' MoS 2 rich with abundant Mo-Mo bonds are about 9 and 12 times above average than those of 2H MoS 2 , correspondingly. Theoretical simulations reveal the high local electron density surrounding the MoMo chains and sites can promote π back-donation, which is beneficial for increasing nitrogen adsorption, strengthening the MN bonds, and reducing the cleavage barrier of the triple NN bond., (© 2021 Wiley-VCH GmbH.)

Ethanol is preferred to be oxidized into CO 2 for the construction of a high-performance direct ethanol fuel cell since this complete ethanol oxidation reaction (EOR) transfers 12 electrons. However, this EOR is sluggish and has the low activity as well as poor selectivity. To promote such a favorable EOR, more exactly the cleavage selectivity of CC bonds in ethanol, phosphorus-doped silver-core-and-Pd-shell catalysts (denoted as Ag@PdP) are designed and synthesized. In the alkaline media, a Ag@Pd 2 P 0.2 catalyst is superior toward EOR into CO 2 . It exhibits seven times higher mass activity and six times higher selectivity than the benchmark Pd/C catalyst. As confirmed by means of density functional theory calculation and in situ Fourier-transform infrared spectroscopy, such high performance stems from an increased adsorption energy of OH radicals on the Pd active sites. Meanwhile, the tensile strain effect of a core-shell structure of this Ag@Pd 2 P 0.2 catalyst favors the formation of adsorbed CH 3 CO intermediate, the key species for the enhanced C-C cleavage into CO 2 , instead of acetate. The proposed way to design and synthesize such high-performance EOR catalysts will explore the practical applications of direct alkaline ethanol fuel cells., (© 2020 The Authors. Small published by Wiley-VCH GmbH.)

The electrocatalytic urea oxidation reaction (UOR) provides more economic electrons than water oxidation for various renewable energy-related systems owing to its lower thermodynamic barriers. However, it is limited by sluggish reaction kinetics, especially by CO 2 desorption steps, masking its energetic advantage compared with water oxidation. Now, a lattice-oxygen-involved UOR mechanism on Ni 4+ active sites is reported that has significantly faster reaction kinetics than the conventional UOR mechanisms. Combined DFT, 18 O isotope-labeling mass spectrometry, and in situ IR spectroscopy show that lattice oxygen is directly involved in transforming *CO to CO 2 and accelerating the UOR rate. The resultant Ni 4+ catalyst on a glassy carbon electrode exhibits a high current density (264 mA cm -2 at 1.6 V versus RHE), outperforming the state-of-the-art catalysts, and the turnover frequency of Ni 4+ active sites towards UOR is 5 times higher than that of Ni 3+ active sites., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)