Controlled growth of a high selectivity interface for seawater electrolysis.

Overall seawater electrolysis is an important direction for the development of hydrogen energy conversion. The key issues include how to achieve high selectivity, activity, and stability in seawater electrolysis reactions. In this report, the heterostructures of graphdiyne-RhOx-graphdiyne (GDY/RhOx/GDY) were constructed by in situ-controlled growth of GDY on RhOx nanocrystals. A double layer interface of sp-hybridized carbon-oxide-Rhodium (sp-C∼O-Rh) was formed in this system. The microstructures at the interface are composed of active sites of sp-C∼O-Rh. The obvious electron-withdrawing surface enhances the catalytic activity with orders of magnitude, while the GDY outer of the metal oxides guarantees the stability. The electron-donating and withdrawing sp-C∼O-Rh structures enhance the catalytic activity, achieving high-performance overall seawater electrolysis with very small cell voltages of 1.42 and 1.52 V at large current densities of 10 and 500 mA cm-2 at room temperatures and ambient pressures, respectively. The compositional and structural superiority of the GDY-derived sp-C-metal-oxide active center offers great opportunities to engineer tunable redox properties and catalytic performance for seawater electrolysis and beyond. This is a typical successful example of the rational design of catalytic systems.

Selectively Growing a Highly Active Interface of Mixed Nb-Rh Oxide/2D Carbon for Electrocatalytic Hydrogen Production.

Tailorable electron distribution of the active sites is widely regarded as the key issue to boost the catalytic activity and provide mechanistic insights into the structure-property-performance relationship. Here, a selective metal atom in situ growth strategy to construct highly active interface of mixed metal atom with different Nby RhOx species on sp-/sp2 -cohybridized graphdiyne (Nby RhOx /GDY) is reported. With this innovative idea implemented, experimental results show that the asymmetric electron distribution and the variation of coordination environment of bimetallic species significantly improve the electrocatalytic activity of Nby RhOx /GDY. Optimal hydrogen evolution reaction (HER) activity is achieved at the Nb/Rh ratio of 0.23, exhibiting excellent HER activity with the small overpotentials of 14 and 10 mV at 10 mA cm-2 in alkaline and neutral electrolytes. The data show the strong potential for real-system application of such catalysts, which outperform commercial Pt/C (20 wt%). These results shown in this study represent a platform for designing novel catalytic materials by selectively introducing metal atoms on different supports, which can be used as a general method extended to other catalytic systems.

Bimetallic Mixed Clusters Highly Loaded on Porous 2D Graphdiyne for Hydrogen Energy Conversion.

There is no doubt that hydrogen energy can play significant role in promoting the development and progress of modern society. The utilization of hydrogen energy has developed rapidly, but it is far from the requirement of human. Therefore, it is very urgent to develop methodologies and technologies for efficient hydrogen production, especially high activity and durable electrocatalysts. Here a bimetallic oxide cluster on heterostructure of vanadium ruthenium oxides/graphdiyne (VRuOx /GDY) is reported. The unique acetylene-rich structure of graphdiyne achieves outstanding characteristics of electrocatalyst: i) controlled preparation of catalysts for achieving multiple-metal clusters; ii) regulation of catalyst composition and morphology for synthesizing high-performance catalysts; iii) highly active and durable hydrogen evolution reaction (HER) properties. The optimal porous electrocatalyst (VRu0.027 Ox /GDY) can deliver 10 mA cm-2 at low overpotentials of 13 and 12 mV together with robust long-term stability in alkaline and neutral media, respectively, which are much smaller than Pt/C. The results reveal that the synergism of different components can efficiently facilitate the electron/mass transport properties, reduce the energy barrier, and increase the active site number for high catalytic performances.