Nanozymes hold huge potential in various fields, but their much lower catalytic activities than natural enzymes greatly limit their extensive applications. Recent studies indicated that an enhanced enzyme-like activity could be obtained by decreasing the particle size through rational design because smaller nanoparticles (NPs) have larger surface-area-to-volume ratios and more unsaturated sites, which are beneficial to the adsorption of reactant species. However, ultrasmall NPs have low adsorption energy and poor stability, which makes the synthesis of superstable and ultrasmall nanozymes extremely difficult. Several interesting works reported that the encapsulation of ultrasmall NPs with few-layer carbon shells could effectively protect them from dissolution and agglomeration, and meanwhile, their catalytic activities were not greatly affected. Herein, we report a superstable and ultrasmall graphene encapsuled CoRu nanocrystal ([email protected]) with the CoRu alloy confined in the nanospace of few-layer graphene via the chemical vapor deposition method. It shows excellent corrosion resistance in aqua regia due to the protection of the chemically inert graphitic shell. The intrinsic peroxidase-, oxidase-, and catalase-like activities of the [email protected] are systematically explored, including the influence of the concentration, pH, and temperature on the enzyme-like activity, steady-state kinetic analysis, and catalytic oxidation mechanism study. Significantly, the [email protected] shows an excellent and ultrastable enzyme-like activity with the treatment of high temperatures, buffered solutions, or NaCl solutions probably because the graphene layer protects it from dissolution and agglomeration efficiently. We believe that the proposed graphene confinement strategy could highlight the direction of highly active, superstable, and ultrasmall-sized nanozyme preparation.

中文翻译：

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超稳定超小石墨烯包裹CoRu纳米晶的酶模拟活性研究

纳米酶在各个领域具有巨大的潜力，但是它们的催化活性比天然酶低得多，极大地限制了它们的广泛应用。最近的研究表明，通过合理设计减小颗粒尺寸可以获得增强的类酶活性，因为较小的纳米颗粒（NPs）具有更大的表面积与体积比和更多的不饱和位点，有利于反应物的吸附物种。然而，超小纳米颗粒的吸附能低、稳定性差，这使得超稳定和超小纳米酶的合成极其困难。一些有趣的工作报道，用少层碳壳包裹超小纳米颗粒可以有效地保护它们免受溶解和团聚，同时它们的催化活性没有受到很大影响。在此，我们报告了一种超稳定和超小石墨烯封装的 CoRu 纳米晶体（[电子邮件保护]），通过化学气相沉积方法将 CoRu 合金限制在几层石墨烯的纳米空间中。由于化学惰性石墨壳的保护，它在王水中显示出优异的耐腐蚀性。系统研究了[被保护的电子邮件]固有的过氧化物酶，氧化酶和过氧化氢酶样活性，包括浓度，pH和温度对酶样活性的影响，稳态动力学分析和催化氧化机制研究。值得注意的是，[email protected] 在处理高温、缓冲溶液、或 NaCl 溶液，可能是因为石墨烯层有效地保护它免于溶解和团聚。我们相信所提出的石墨烯限制策略可以突出高活性、超稳定和超小尺寸纳米酶制备的方向。