Ammonia borane (AB) is an excellent hydrogen-storage material for fuel cells. However, the release of H₂ from AB is limited by using expensive noble-metal-based catalysts. Here, we build up a cube-like Cu_0.5Co_0.5O nanostructure on reduced graphene oxide (rGO) for the high-efficiency hydrolysis of AB. The Cu_0.5Co_0.5O-rGO catalyst can achieve a high total turnover frequency of 81.7 (H₂) mol·(Cat-metal)mol⁻¹·min⁻¹, which is one of the best values ever reported for noble metal-free catalysts. The catalyst also shows good stability by maintaining 88.3% activity after 5 runs. Synchrotron radiation-based in situ X-ray absorption spectroscopy is used to probe the catalytic mechanism, which reveals that the Cu sites in the catalyst can activate water and then collaborate with Co to anchor the AB molecules for high catalytic activity. The high performance of Cu_0.5Co_0.5O-rGO can be attributed to both the coordination of Cu and Co in the cube-like structure and the metal-support interaction. The deactivation of Cu_0.5Co_0.5O-rGO after 10 cycles is also studied, which can be attributed to the loss of cube-like structure and the reduction of Cu and Co. The in-depth understanding of the catalytic process may significantly pave the way for the rational design of highly efficient catalysts.

中文翻译：

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还原型氧化石墨烯上的立方状CuCoO纳米结构，用于从氨硼烷生成H ₂ †

硼烷氨（AB）是用于燃料电池的出色储氢材料。然而，通过使用昂贵的贵金属基催化剂限制了H ₂从AB中的释放。在这里，我们在还原的氧化石墨烯（rGO）上建立了立方体状的Cu _0.5 Co _0.5 O纳米结构，以实现AB的高效水解。Cu _0.5 Co _0.5 O-rGO催化剂可达到81.7（H ₂）mol·（Cat-metal）mol ^-1 ·min ^-1的高总周转频率，这是有史以来关于贵金属的最佳值之一。游离催化剂。在5次运行后，通过保持88.3％的活性，该催化剂还显示出良好的稳定性。基于同步辐射的原位X射线吸收光谱用于探测催化机理，这表明催化剂中的Cu位置可以活化水，然后与Co协同锚定AB分子以实现高催化活性。Cu _0.5 Co _0.5 O-rGO的高性能可归因于Cu和Co在立方体状结构中的配位以及金属与载体之间的相互作用。还研究了10个循环后Cu _0.5 Co _0.5 O-rGO的失活，这可能归因于立方体结构的损失以及Cu和Co的还原。对催化过程的深入了解可能会为合理设计高效催化剂的方法。