Investigating lightweight electromagnetic microwave absorption materials is still urgent because of the issue related to the electromagnetic pollution or military defense. Our findings indicate that core−shell MnO@carbon nanowires (MnO@C NWs) achieve substantially enhanced microwave absorption, suggesting the suitable impedance matching induced by the synergetic effect between MnO and carbon. Furthermore, the peapod-like MnO@C NWs with internal void space can be facially synthesized by partial etching of core−shell MnO@C NWs. The peapod-like MnO@C NWs with internal voids/cavities exhibit dramatically enhanced electromagnetic microwave absorption property when the carbon content is about 64 wt %, a minimum reflection loss (RL) of −55 dB at 10 wt % loading was observed at 13.6 GHz, and the bandwidth of RL less than −10 dB (90% absorption) covers 6.2 GHz at the thickness of 2 mm. The excellent electromagnetic microwave absorption performance is superior to the most of MnO x /C composites in the literatures, which probably benefits from the dielectric polarization among conductive network structure between MnO and carbon, as well as the multiple reflection and absorption induced by internal void space. Our work is expected to pave an effective way to extend the electromagnetic microwave absorption performance of MnO/C composites through partial etching to create a void space.

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Synergistic optimization of the elementary steps of water dissociation and hydrogen desorption for the hydrogen evolution reaction (HER) in alkaline media is a challenge. Herein, the Ru cluster anchored on a trace P‐doped defective TiO2 substrate (Ru/P‐TiO2) was synthesized as an electrocatalyst for the HER; it exhibited a commercial Pt/C‐like geometric activity and an excellent mass activity of 9984.3 mA mgRu−1 at −0.05 V vs. RHE, which is 34.3 and 18.7 times higher than that of Pt/C and Ru/TiO2, respectively. Experimental and theoretical studies indicated that using a rutile‐TiO2‐crystal‐phase substrate enhanced the HER activity more than the anatase phase. Rich surface oxygen vacancies on rutile‐TiO2 facilitated the adsorption and dissociation of water, while the partial substitution of Ti4+ with P5+ enhanced H2 generation by facilitating hydrogen spillover from the Ru site to the surface P site, synergistically enhancing the HER activity.

Noble-metal-free catalytic hydrogenation of nitroarenes is achieved through the rational design of atomically dispersed Ni sites on N-doped porous carbon. The outstanding activity of the catalyst originates from the atomic dispersion of Ni active sites with a high Ni–N3 content.

applications. As a member of platinumgroup metals, ruthenium (Ru) possesses lower prices than Pt, Pd, and Ir and is extensively applied in a lot of industrial reactions. Moreover, its bond strength with hydrogen is similar to that of Pt, making it a promising alternative for catalyzing the HER. [4] Although Ru has potentially superior electrochemical HER activity, its cost, overpotential, and electrochemical durability still need to be improved to realize its wide applications. [4b,c,5] There are generally two strategies to enhance the activity of catalysts: i) improving the intrinsic activity of each active site; ii) increasing the number of active sites. [6] It has been proven that introducing foreign atoms into Ru lattices can regulate the electronic structure to improve the intrinsic activity of Ru-based electrocatalysts. [4b,7] For instance, Li et al. found that the chemical coupling of Ni into Ru could decrease the d-band center of the electrocatalyst, which would induce a relatively moderate binding energy of metal-hydrogen. [7b] Zhao and co-workers demonstrated that the electronic manipulation through P-doping in Ru nanoparticles could realize the electronic manipulation to obtain the optimized ΔG H* toward HER. [7c] The introduction of cheap foreign atoms can also reduce the consumption of precious metals. Furthermore, some studies indicated that the dual doping with heteroatom and transition metal could form multi-active centers and promote an optimal balance for surface chemical states. [8] Although there are rare reports about dual doping on Ru-based catalysts, we believe that the heteroatom and transition metal dual doping into Ru lattices is an effective way to improve their intrinsic activity.In addition, decreasing the particle size has been confirmed as an effective means to increase the number of active sites on a given electrode. [9] To achieve this goal, a strategy of uniformly dispersing and sequestering metal nanoparticles in a 2D carbon structure is often applied. [7a,10] For example, Yang et al. used a sulfur-anchoring method to synthesize Pt-based intermetallic nanoparticles libraries with an average size of about 5 nm on sulfur-doped carbon matrix, exhibiting excellent activities for proton-exchange membrane fuel cells applications. [10] Loading metal nanoparticles on heteroatom doped porous carbon matrix to form heterostructures could not only reduce the consumption of precious metal, but also greatly enhance the stability and alter the local electronic structures at Rational design of efficient hydrogen evolution reaction (HER) electrocatalysts for mass production of hydrogen via electrochemical water splitting is a challenging but pressing task. Herein, an in situ dual doping engineering from phosphomolybdic acid encapsulated within the bimetallic metal-organicframeworks strategy to synthesize P,Mo dual doped Ru ultrasmall nanoparticles embedded in P-doped porous carbon (P,Mo-Ru@PC) for efficient HER is proposed. As a result, P,Mo-Ru@PC achieves a low overpotential of 21 at ...