Carbon catalysts with trnsition metal atoms anchored via nitrogen coordination have emerged as promising alternatives to Pt in catalyzing oxygen reduction reaction (ORR). However, the intangible evolution of structure in popular synthetic routes containing pyrolysis leads to discrete and irregular M-N_x sites, resulting in limited descriptors and thus ambiguous understandings of structure-activity relationships. We report here a facile method to synthesize Cu-N_x sites of high homogeneity anchored on carbon substrates through deposition and carbonization of glycoluril on metallic copper surface. The Cu-N_x sites take shape under the surface regulation of metallic copper and preferentially exposed after removal of excess Cu. The optimal catalyst presents efficient activity towards ORR with a half-wave potential of 0.84 V (vs. RHE). More importantly, linear relationships over the catalyst between current densities and electrochemical active surface areas (ECSAs) are derived, suggesting activities countable by ECSAs. The correlation clearly demonstrates the high homogeneity and catalytic accessibility of surface-regulated Cu-N_x sites. The well-elucidated structure-activity relationship identifies Cu-N_x sites as originates of catalytic ORR at an experimental level and sheds light on rational engineering of catalysts containing M-N_x sites.

具有通过氮配位锚定的三价金属原子的碳催化剂已成为催化氧还原反应（ORR）中Pt的有前途的替代品。然而，在包含热解的流行合成路线中，结构的无形演变导致离散和不规则的MN _x位点，导致描述符有限，因此对结构-活性关系的理解不明确。我们在这里报告了一种简便的方法，可以通过在金属铜表面沉积和碳化甘脲来合成锚固在碳基底上的高均一性的Cu-N _x位点。铜氮_x这些位置在金属铜的表面调节下成型，并且在去除多余的Cu后优先暴露出来。最佳催化剂以0.84 V（相对于RHE）的半波电势表现出对ORR的有效活性。更重要的是，得出了电流密度与电化学活性表面积（ECSA）之间催化剂上的线性关系，这表明ECSA可计数的活性。该相关性清楚地表明了表面调节的Cu-N _x位点的高度均一性和催化可及性。充分阐明的结构-活性关系在实验水平上将Cu-N _x位点识别为催化ORR的起源，并为合理设计包含MN _x位点的催化剂提供了启示。