Transition-metal single-atom catalysts present extraordinary activity per metal atomic site, but suffer from low metal-atom densities (typically less than 5 wt% or 1 at.%), which limits their overall catalytic performance. Here we report a general method for the synthesis of single-atom catalysts with high transition-metal-atom loadings of up to 40 wt% or 3.8 at.%, representing several-fold improvements compared to benchmarks in the literature. Graphene quantum dots, later interweaved into a carbon matrix, were used as a support, providing numerous anchoring sites and thus facilitating the generation of high densities of transition-metal atoms with sufficient spacing between the metal atoms to avoid aggregation. A significant increase in activity in electrochemical CO₂ reduction (used as a representative reaction) was demonstrated on a Ni single-atom catalyst with increased Ni loading.

过渡金属单原子催化剂在每个金属原子位点表现出非凡的活性，但金属原子密度低（通常小于 5 wt% 或 1 at.%），这限制了它们的整体催化性能。在这里，我们报告了一种合成单原子催化剂的通用方法，该催化剂具有高达 40 wt% 或 3.8 at.% 的高过渡金属原子负载，与文献中的基准相比有几倍的改进。石墨烯量子点，后来交织到碳基质中，被用作载体，提供了许多锚定位点，从而促进了高密度过渡金属原子的产生，金属原子之间有足够的间距以避免聚集。_{电化学CO 2}活性显着提高 还原（用作代表性反应）在 Ni 单原子催化剂上得到证实，Ni 负载增加。