Catalytic Nanoframes and Beyond

The ever-increasing need for the production and expenditure of sustainable energy is a result of the astonishing rate of consumption of fossil fuels and the accompanying environmental problems. Emphasis is being directed to the generation of sustainable energy by the fuel cell and water splitting technologies. Accordingly, the development of highly efficient electrocatalysts has attracted significant interest, as the fuel cell and water splitting technologies are critically dependent on their performance. Among numerous catalyst designs under investigation, nanoframe catalysts have an intrinsically large surface area per volume and a tunable composition, which impacts the number of catalytically active sites and their intrinsic catalytic activity, respectively. Nevertheless, the structural integrity of the nanoframe during electrochemical operation is an ongoing concern. Some significant advances in the field of nanoframe catalysts have been recently accomplished, specifically geared to resolving the catalytic stability concerns and significantly boosting the intrinsic catalytic activity of the active sites. Herein, general synthetic concepts of nanoframe structures and their structure-dependent catalytic performance are summarized, along with recent notable advances in this field. A discussion on the remaining challenges and future directions, addressing the limitations of nanoframe catalysts, are also provided.

Ternary dendritic nanowires as highly active and stable multifunctional electrocatalysts

Multimetallic nanocatalysts with a controlled structure can provide enhanced catalytic activity and durability by exploiting electronic, geometric, and strain effects. Herein, we report the synthesis of a novel ternary nanocatalyst based on Mo doped PtNi dendritic nanowires (Mo-PtNi DNW) and its bifunctional application in the methanol oxidation reaction (MOR) at the anode and the oxygen reduction reaction (ORR) at the cathode for direct methanol fuel cells. An unprecedented Mo-PtNi DNW structure can combine multiple structural attributes of the 1D nanowire morphology and dendritic surfaces. In the MOR, Mo-PtNi DNW exhibits superior activity to Pt/C and Mo doped Pt dendritic nanowires (Mo-Pt DNW), and excellent durability. Furthermore, Mo-PtNi DNW demonstrates excellent activity and durability for the ORR. This work highlights the important role of compositional and structural control in nanocatalysts for boosting catalytic performances.