Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Korea.
Department of Chemical and Biomolecular Engineering , Yonsei University , Seoul 120-749 , Korea.
ACS Appl Mater Interfaces. 2019 Nov 20;11(46):43460-43465. doi: 10.1021/acsami.9b11619. Epub 2019 Nov 11.
Despite the remarkable electronic and mechanical properties of graphene, improving the catalytic activity of the atomically flat, inert, and stable carbon network remains a challenging issue in both fundamental and application studies. In particular, the adsorption of most molecules and ions, including hydrogen (H or H), on graphene is not favorable, underlining the challenge for an efficient electrochemical catalytic reaction on graphene. Various defects, edges, and functionalization have been suggested to resolve the catalytic issue in graphene, but cost-effectiveness and active catalysis with graphene have not been achieved yet. Here, we introduce dynamic stacking of reduced graphene oxide (rGO) with spontaneously generated hydrogen bubbles to form an efficient electrochemical catalyst with a graphene derivative; the in operando stacking of rGO, without using a high-temperature-based heteroatom doping process or plasma treatment, creates a large catalytic surface area with optimized edges and acidic groups in the rGO. Thus, the uniquely formed stable carbon network achieves active hydrogen evolution with a Tafel slope of 39 mV·dec and a double layer capacitance of 12.41 mF·cm, which breaks the conventional limit of graphene-based catalysis, suggesting a promising strategy for metal-free catalyst engineering and hydrogen production.
尽管石墨烯具有显著的电子和机械性能，但改善原子级平坦、惰性和稳定的碳网络的催化活性在基础和应用研究中仍然是一个具有挑战性的问题。特别是，大多数分子和离子，包括氢（H 或 H），在石墨烯上的吸附是不利的，这突出了在石墨烯上进行高效电化学催化反应的挑战。已经提出了各种缺陷、边缘和功能化来解决石墨烯中的催化问题，但尚未实现具有成本效益和活性的石墨烯催化。在这里，我们引入了自发产生的氢气泡还原氧化石墨烯（rGO）的动态堆叠，以形成具有石墨烯衍生物的高效电化学催化剂；rGO 的原位堆叠，无需使用基于高温的杂原子掺杂过程或等离子体处理，在 rGO 中创建了具有优化边缘和酸性基团的大催化表面积。因此，独特形成的稳定碳网络实现了活性的氢析出，其塔菲尔斜率为 39 mV·dec 和双层电容为 12.41 mF·cm，打破了基于石墨烯的催化的传统限制，为无金属催化剂工程和制氢提供了一种有前景的策略。
