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Direct borohydride fuel cells (DBFCs) convert borohydride (NaBH4) chemical energy into clean electricity. However, catalytic active site deactivation in NaBH4 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. [ABSTRACT FROM AUTHOR]

Finding a high CO‐tolerance Pt‐based catalyst plays a critical role for direct methanol fuel cells. Therefore, it is necessary to design controllable nanostructure and composition. Herein, a synthesis of ultrathin PtNiGaSnMoRe senary nanowires (SNWs) that features the virtues of partial amorphous structure, multimetallic ensembles, and ultrathin diameter is reported. For the alkaline methanol oxidation reaction (MOR), the SNWs deliver an excellent mass activity of 6.2 A mg−1Pt and a specific activity of 12.3 mA cm−2, respectively. More significantly, after undergoing 10 000 s of a durability test, its mass activity remains 13.0 times higher than that of commercial Pt/C catalyst, which is mainly attributed to the faster CO‐intermediate (CO*) removal and advanced nanostructure. In situ Fourier transform infrared (FTIR) spectroscopies and CO stripping experiments indicate its remarkable resistance to CO poisoning. Theoretical studies further reveal that the SNWs enable reduced energy barriers for the conversion of CO* into COOH* derived from the decreased CO* binding and intensified OH adsorption that accelerate the combination of both, thus essentially improving the MOR performance and CO tolerance. [ABSTRACT FROM AUTHOR]

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 CO2 desorption steps, masking its energetic advantage compared with water oxidation. Now, a lattice‐oxygen‐involved UOR mechanism on Ni4+ active sites is reported that has significantly faster reaction kinetics than the conventional UOR mechanisms. Combined DFT, 18O isotope‐labeling mass spectrometry, and in situ IR spectroscopy show that lattice oxygen is directly involved in transforming *CO to CO2 and accelerating the UOR rate. The resultant Ni4+ 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 Ni4+ active sites towards UOR is 5 times higher than that of Ni3+ active sites. [ABSTRACT FROM AUTHOR]

Architectural engineering of noble metal nanocrystals can result in structural diversity and complexity, thereby providing catalysts with multifunctional properties. Herein, a unique Sierpinski gasket-like Pt–Ag octahedral alloy nanostructure with a three-dimensional hyperbranched architecture containing abundant well-defined Pt-rich {111} stable facets and dense low-coordinated active sites is reported. Unlike the well-accepted long-range limiting diffusion govened growth model for fractal structures, our success relies on creating local depletion layer near the crystal surface by surfactant. The as-prepared Sierpinski gasket-like Pt–Ag octahedral nanocrystals allows us to achieve three milestones for electrocatalysts, i.e. high catalytic activity, great durability, and stability towards the methanol oxidation reaction in acidic media. Specifically, the catalyst shows a high specific activity (6.61 mA cm−2, is superior than most of reported Pt-based catalysts), outstanding CO ads -poisoning tolerance and stability (the morphology and composition of the catalyst are preserved after 2000 cycles). This study points to a new approach to develop highly efficient catalysts in the form of fractal nanostructures with structural diversity and complexity to balance the delicate trade-off between activity and stability of catalysts. Image 1 • A new kind of three-dimensional fractal Sierpinski gasket-like octahedral Pt-Ag alloy nanocrystals are synthetized. • A new synthetic strategy for fractal structures based on surfactant induced local diffusion-limited growth was developed. • They achieve high activity, great durability and stability simultaneously towards the methanol oxidation in acidic meida. [ABSTRACT FROM AUTHOR]

Direct conversion of one‐carbon (C1) compounds to two‐carbon (C2) and multi‐carbon compounds remains a critical challenge for converting non‐petroleum resources to valuable chemicals or fuels. The key issue is the selective activation of C1 compounds, methanol, as well as the controlled formation of carbon‐carbon (C−C) bonds. Herein, we achieve the direct electrocatalytic methanol to ethanol, an important chemical and energy candidate, with methanol conversion, ethanol selectivity, and faradic efficiency of 257.0 g ⋅ m−2 ⋅ h−1, 95.1 %, and 12.5 %, respectively. Furthermore, the appropriate participation of water, as a by‐product from methanol electrocatalysis, in hydrogen evolution reaction (HER) facilitates electrocatalytic reaction of methanol. Mechanistic studies reveal hydroxymethyl and methyl radicals are formed on the electropositive low‐valent metal sites and electronegative carbon vacancies, respectively, and then combined with each other to form ethanol at the metal/carbon interface. This work opens a unique route for high‐efficient concerted redox conversion of methanol reactant to ethanol. [ABSTRACT FROM AUTHOR]