Isolating the Electrocatalytic Activity of a Confined NiFe Motif within Zirconium Phosphate
Isolating the Electrocatalytic Activity of a Confined NiFe Motif within Zirconium Phosphate
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DOI：
10.1002/aenm.202003545
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发表时间：
2021-04-14
影响因子：
27.8
通讯作者：
Jaramillo, Thomas F.
中科院分区：
文献类型：
--
作者：
Sanchez, Joel;Stevens, Michaela Burke;Jaramillo, Thomas F.
改进电催化需要独特类别的活性位点基序。在此，设计并分离了一种新催化剂基序的活性，用于由限制在层状磷酸锆基质内的镍-铁过渡金属电催化剂产生的析氧反应（OER）。研究发现，通过最佳插层，与 0.1 m KOH 中更传统的表面吸附系统相比，受限 NiFe 催化剂的质量活性提高了一个数量级。有趣的是，与已知的富铁 OER 催化剂相比，层状结构内的有限环境也稳定了富铁组合物 (90%)，具有出色的质量活性。通过控制和将惰性分子接枝到外表面，证明插入的 Ni/Fe 物质在催化过程中留在夹层内并充当活性位点。在确定可能的结构（wycherproofite）后，密度泛函理论被证明与观察到的实验成分趋势相关。进一步证明，该基序的活性改善与有限空间内的铁和水含量/成分相关。这项工作强调了通过磷酸锆实现催化增强的可能性，并将插层物质与表面/边缘物质的活性分开，从而为在独特的纳米级化学环境中开发和理解催化剂开辟了新途径。
Unique classes of active-site motifs are needed for improved electrocatalysis. Herein, the activity of a new catalyst motif is engineered and isolated for the oxygen evolution reaction (OER) created by nickel-iron transition metal electrocatalysts confined within a layered zirconium phosphate matrix. It is found that with optimal intercalation, confined NiFe catalysts have an order of magnitude improved mass activity compared to more conventional surface-adsorbed systems in 0.1 m KOH. Interestingly, the confined environments within the layered structure also stabilize Fe-rich compositions (90%) with exceptional mass activity compared to known Fe-rich OER catalysts. Through controls and by grafting inert molecules to the outer surface, it is evidenced that the intercalated Ni/Fe species stay within the interlayer during catalysis and serve as the active site. After determining a possible structure (wycherproofite), density functional theory is shown to correlate with the observed experimental compositional trends. It is further demonstrated that the improved activity of this motif is correlated to the Fe and water content/composition within the confined space. This work highlights the catalytic enhancement possibilities available through zirconium phosphate and isolates the activity from the intercalated species versus surface/edge ones, thus opening new avenues to develop and understand catalysts within unique nanoscale chemical environments.