The Front Cover shows how direct borohydride fuel cells (DBFCs) convert borohydride chemical energy into clean electricity, which can provide electric energy for unmanned aerial vehicles and other electrical equipment. In order to enhance the electrochemical borohydride oxidation reaction (eBOR) at the anode, this study proposed a strategy to regulate active sites in Co-based catalysts by using polypyrrole modification. The polypyrrole-modified carbon support regulates the charge distribution around Co species, optimizing adsorption and desorption of intermediates. This study opens a new avenue for the design and development of electrocatalysts with high eBOR performance by manipulating the active sites with polymers. More information can be found in the Research Article by B. Zhang and co-workers.
Direct borohydride fuel cell (DBFC) is considered a promising energy storage device due to its high theoretical cell voltage and energy density. For DBFC, an Au catalyst has been used as an anode for achieving an ideal eight-electron reaction. However, the poor activity of the Au catalyst for borohydride oxidation reaction (BOR) limits its large-scale application because of the weak BH
Electrochemical carbon monoxide (CO) reduction to high-energy-density fuels provides a potential way for chemical production and intermittent energy storage. As a valuable C3 species, n-propanol still suffers from a relatively low Faradaic efficiency (FE), sluggish conversion rate and poor stability. Herein, we introduce an "atomic size misfit" strategy to modulate active sites, and report a facile synthesis of a Pb-doped Cu catalyst with numerous atomic Pb-concentrated grain boundaries. Operando spectroscopy studies demonstrate that these Pb-rich Cu-grain boundary sites exhibit stable low coordination and can achieve a stronger CO adsorption for a higher surface CO coverage. Using this Pb-Cu catalyst, we achieve a CO-to-n-propanol FE (FEpropanol) of 47 ± 3% and a half-cell energy conversion efficiency (EE) of 25% in a flow cell. When applied in a membrane electrode assembly (MEA) device, a stable FEpropanol above 30% and the corresponding full-cell EE of over 16% are maintained for over 100 h with the n-propanol partial current above 300 mA (5 cm2 electrode). Furthermore, operando X-ray absorption spectroscopy and theoretical studies reveal that the structurally-flexible Pb-Cu surface can adaptively stabilize the key intermediates, which strengthens the *CO binding while maintaining the C-C coupling ability, thus promoting the CO-to-n-propanol conversion.
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