Ordered Macroporous Superstructure of Nitrogen‐Doped Nanoporous Carbon Implanted with Ultrafine Ru Nanoclusters for Efficient pH‐Universal Hydrogen Evolution Reaction

Abstract

The massive depletion of fossil fuels has led to severe energy and environmental crisis, which urgently needs an in-depth research on the exploration of sustainable energy. Among various energy sources, hydrogen (H 2) is considered to be one of the most potential alternatives to traditional fossil fuels owing to its high energy density and environmental friendliness. [1] Electrochemical hydrogen evolution reaction (HER) is an attracting and scalable technology to split water into H 2 , which can use the renewable electricity as power to realize a hydrogen-based economy. [2] Metals with good conductivity and proton activation are promising electrocatalysts for HER. The past years have witnessed the great progress on metal-based catalysts for HER, where the noble metals, such as platinum (Pt) with near-zero overpotential and a very low Tafel slope for HER, are well known to meet the requirements in terms of commercial application. [3] However, the cherish scarcity and poor stability The electrochemical hydrogen evolution reaction (HER) is an attractive technology for the mass production of hydrogen. Ru-based materials are promising electrocatalysts owing to the similar bonding strength with hydrogen but much lower cost than Pt catalysts. Herein, an ordered macroporous superstructure of N-doped nanoporous carbon anchored with the ultrafine Ru nanoclusters as electrocatalytic micro/nanoreactors is developed via the thermal pyrolysis of ordered macroporous single crystals of ZIF-8 accommodating Ru(III) ions. Benefiting from the highly interconnected reticular macro-nanospaces, this superstrucure affords unparalleled performance for pH-universal HER, with order of magnitude higher mass activity compared to the benchmark Pt/C. Notably, an exceptionally low overpotential of only 13 mV@10 mA cm −2 is required for HER in alkaline solution, with a low Tafel slope of 40.41 mV dec −1 and an ultrahigh turnover frequency value of 1.6 H 2 s −1 at 25 mV, greatly outperforming Pt/C. Furthermore, the hydrogen generation rates are almost twice those of Pt/C during practical overall alkaline water splitting. A solar-to-hydrogen system is also demonstrated to further promote the application. This research may open a new avenue for the development of advanced electrocatalytic micro/nanoreactors with controlled morphology and excellent performance for future energy applications.

Laser‐Irradiated Holey Graphene‐Supported Single‐Atom Catalyst towards Hydrogen Evolution and Oxygen Reduction

“…[28] The deconvoluted high-resolution spectra of the NMGO sample are given in Figure S3b, Supporting Information. It shows wellfitted four individual peaks, including oxidized N, pyridinic-N, pyrrolic-N, and graphitic-N. [27,29] It has been reported that pyridinic N content promotes synthesized catalyst's catalytic activity. [29] Further, rich pyridinic N contents can be served as active sites for anchoring single metal atoms.…”

“…[25,26] It is reported that micropores in nanocarbon matrix are not very supportive towards mass transportation in terms of high current density. [27] Other reports suggest that the metal SAC case's acid leaching process opens maximum pores during the synthesis process to enlarge the surface area. Reports [25,26] evidenced that ordered mesopores are majorly hosting metal-doped (MNx) active sites for catalytic applications.…”

Electrocatalytic Hydrogen Evolution Reaction Related to Nanochannel Materials

“…For example, an ordered macro-meso-microporous and N-doped carbon superstructure anchored with a Ru nanocluster (Ru/OMSNNC) has been prepared by Xu and co-workers. [37] The SEM and TEM images show the macrochannels with the size of about 190 nm and surrounding walls of about 25 nm (Figure 10a). On the other side, the presence of a mesochannel and microchannel has been verified by the high N 2 absorption method and the average sizes are about 3.8 and 1.1 nm, respectively.…”

“…Ascribing to the optimal hydrogen binding energy provided by hydroxylated intermetallic Co 3 Mo and the high electron/ion transport property of the hierarchical porous skeleton, the overpotential at 10 mA cm À2 (Figure 10d) and Tafel slope of the Co 3 Mo-supported Cu skeleton (Co 3 Mo/Cu) were measured to be %12 mV and %40 mV dec À1 , respectively. In addition, current density as high [37] Copyright 2021, Wiley. c) Cross-sectional SEM image and d) HER LSV curves in 1 M KOH for Co 3 Mo/Cu, respectively.…”

“…a) SEM image and b) LSV curves in 1 M KOH for Ru/OMSNNC, respectively. a,b) Reproduced with permission [37]. Copyright 2021, Wiley.…”