Ritacco Ida, Santoriello Giuseppe, Gatta Gianluca, Farnesi Camellone Matteo, Caporaso Lucia
Dipartimento di Chimica e Biologia, Università degli Studi di Salerno, via Giovanni Paolo II 132, Fisciano, Salerno 84084, Italy.
Dipartimento di Medicina di Precisione Divisione di Radiologia, Università della Campania Luigi Vanvitelli, Napoli 80131, Italy.
ACS Appl Mater Interfaces. 2025 Jul 9;17(27):39708-39718. doi: 10.1021/acsami.5c08441. Epub 2025 Jun 16.
The oxygen reduction reaction (ORR), which converts molecular oxygen (O) into water (HO), is critical for renewable energy transformation processes. However, its industrial application is hindered by long conversion times. Recent studies suggest that transition metal clusters deposited on graphene are promising candidates for ORR catalysis. In this work, we employed density functional theory (DFT) calculations to explore the thermodynamically most stable energy profile of the ORR on pentamer metal clusters (Fe, Co, and Pt) supported on undoped graphene and nitrogen-doped graphene (for Fe), under standard electrochemical conditions (pH = 0 and = 0). Both the "standard" intermediates (*OOH, *O, *OH) and the "unconventional" intermediates (OOH, OHOH) were studied, analyzing thermodynamic stability, adsorption energies, and the influence of the implicit water solvent. Our results reveal that the inclusion of "unconventional" intermediates significantly alters the reaction thermodynamics, presenting a new pathway that is energetically more favorable than the classical one. Catalytic performance predictions, based on the theoretical overpotential (η), indicate that the four catalysts exhibit good stability and high activity in both reduction mechanisms. In particular, Fe@NGr shows the best catalytic performance in the "unconventional" mechanism, with an η close to zero. This study, for the first time, demonstrates how the metal cluster and the support's electronic and structural properties influence the stability of ORR intermediates and catalytic performance. The improved performance of Fe@NGr in the "unconventional" mechanism highlights the importance of selecting the right metal and engineering the graphene support, particularly through N-doping, for the rational design of low-cost, high-performance catalysts.
氧还原反应（ORR）可将分子氧（O）转化为水（H₂O），这对可再生能源转化过程至关重要。然而，其工业应用因转化时间长而受阻。最近的研究表明，沉积在石墨烯上的过渡金属簇是ORR催化的有前途的候选材料。在这项工作中，我们采用密度泛函理论（DFT）计算，探索在标准电化学条件（pH = 0和μ = 0）下，未掺杂石墨烯和氮掺杂石墨烯（对于Fe）负载的五聚体金属簇（Fe、Co和Pt）上ORR的热力学最稳定能量分布。研究了“标准”中间体（*OOH、*O、*OH）和“非常规”中间体（OOH、OHOH），分析了热力学稳定性、吸附能以及隐式水溶剂的影响。我们的结果表明，“非常规”中间体的纳入显著改变了反应热力学，呈现出一条在能量上比经典途径更有利的新途径。基于理论过电位（η）的催化性能预测表明，这四种催化剂在两种还原机制中均表现出良好的稳定性和高活性。特别是，Fe@NGr在“非常规”机制中表现出最佳的催化性能，η接近零。这项研究首次证明了金属簇以及载体的电子和结构性质如何影响ORR中间体的稳定性和催化性能。Fe@NGr在“非常规”机制中性能的提高突出了选择合适的金属以及对石墨烯载体进行工程设计（特别是通过氮掺杂）对于合理设计低成本、高性能催化剂的重要性。
