Formaldehyde is a typical indoor air pollutant that has posed severely adverse effects on human health. Herein, a novel FeCo alloy nanoparticle-embedded nitrogen-doped carbon (FeCo@NC) was synthesized with the aim of tailoring the transition-metal d-band structure toward an improved formaldehyde oxidation activity for the first time. A unique core@shell metal–organic frameworks (MOFs) architecture with a Fe-based Prussian blue analogue core and Co-containing zeolite imidazole framework shell was firstly fabricated. Then, Fe and Co ion alloying was readily achieved owing to the inherent MOF porosity and interionic nonequilibrium diffusion occurring during pyrolysis. High-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectra confirm that small FeCo alloys in situ form in FeCo@NC, which exhibits a higher formaldehyde removal efficiency (93%) than the monometallic Fe-based catalyst and a remarkable CO₂ selectivity (85%) at room temperature. Density functional theory calculations indicate the number of electrons transferred from the metal core to the outer carbon layer is altered by alloying Fe and Co. More importantly, a downshift in the d-band center relative to the Fermi level occurs from − 0.93 to − 1.04 eV after introducing Co, which could alleviate the adsorption of reaction intermediates and greatly improve the catalytic performance.

甲醛是一种典型的室内空气污染物，对人体健康造成了严重的不利影响。在此，合成了一种新型 FeCo 合金纳米颗粒嵌入的氮掺杂碳 (FeCo@NC)，目的是首次调整过渡金属 d 带结构以提高甲醛氧化活性。首次制造了具有铁基普鲁士蓝类似物核和含钴沸石咪唑骨架壳的独特核@壳金属-有机框架（MOF）结构。然后，由于固有的 MOF 孔隙率和热解过程中发生的离子间非平衡扩散，很容易实现 Fe 和 Co 离子合金化。高角度环形暗场扫描透射电子显微镜和 X 射线吸收精细结构光谱证实，在 FeCo@NC 中原位形成了小的 FeCo 合金，₂选择性（85%）在室温下。密度泛函理论计算表明，从金属核转移到外碳层的电子数量因 Fe 和 Co 合金化而改变。更重要的是，d 带中心相对于费米能级的下降从 - 0.93 到 - 1.04引入Co后的eV，可以减轻反应中间体的吸附，大大提高催化性能。