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It is of practical importance to develop a stable and accessible methane combustion catalyst which could retain an excellent activity under drastic conditions. Herein, we introduce a facile approach to extend the stability of conventional Pd/Al2O3 catalysts through tailoring the pore size of mesoporous aluminas (MAs) and the interaction between Pd and Al. By modulating the addition of templates (deoxycholic acid and polyvinylpyrrolidone), a series of MAs with tunable and uniform pore size were obtained through a designed sol–gel method. Unexpectedly, Pd/MA-800-5 catalyst prepared with relatively large pore size (ca. 12 nm) MAs exhibited an efficient and sustained performance under a variety of operating conditions, while those prepared with small pore size (ca. 5–7 nm) MAs suffered from a significant loss of activity during high temperature cyclic reactions (280–850 °C) due to the decomposition of confined PdO. The enhancement could be attributed to the suitable particle size, higher crystallinity, generated active sites, improved reducibility, and thermal stability of PdO species. Moreover, the variation of pore size also resulted in a different reaction mechanism. Such a pore size promotion strategy effectively invoked a superior catalytic performance while keeping the catalyst components simple, which can be extended to prepare other high-performance metal oxide-supported catalysts for catalytic applications.

The development of highly efficient and cheap electrocatalysts for the oxygen evolution reaction (OER) is highly desirable in typical water-splitting electrolyzers to achieve renewable energy production, yet it still remains a huge challenge. Herein, we have presented a simple procedure to construct a new nanofibrous hybrid structure with the interface connecting the surface of CeO 2 and CoO as a high-performance electrocatalyst toward the OER through an electrospinning−calcination−reduction process. The resultant CeO 2 −CoO nanofibers exhibit excellent electrocatalytic properties with a small overpotential of 296 mV at 10 mA cm −2 for the OER, which is superior to many previously reported nonprecious metal-based and commercial RuO 2 catalysts. Furthermore, the prepared CeO 2 −CoO nanofibers display remarkable long-term stability, which can be maintained for 130 h with nearly no attenuation of OER activity in an alkaline electrolyte. A combined experimental and theoretical investigation reveals that the excellent OER properties of CeO 2 -CoO nanofibers are due to the unique interfacial architecture between CeO 2 and CoO, where abundant oxygen vacancies can be generated due to the incomplete matching of atomic positions of two parts, leading to the formation of many low-coordinated Co sites with high OER catalytic activity. This research provides a practical and promising opportunity for the application of heterostructured nonprecious metal oxide catalysts for high-efficiency electrochemical water oxidation.

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Herein, an isolated hydrogen atom absorbed on penta-graphene (PG) was predicted to induce magnetic moments and tune the electronic properties of penta-graphene and was systematically studied using first-principles calculations. The adsorption energy and formation energy calculations suggest that magnetic penta-graphene (M-PG) and weak magnetic penta-graphene (WM-PG) of hydrogen-absorbed PG systems are energetically the most favorable states among the possible hydrogen-absorbed configurations. The hydrogen atom adsorbed on the PG sheet can effectively tune the electronic properties of PG and change it from a semiconductor to half-metallic. In the M-PG system, this spinpolarized state is essentially localized on the three-fold coordinated C atoms in the first layer opposite to that where the hydrogen atom is chemisorbed. Through changing the bond angle and bond length of the adsorbed hydrogen atom on the PG system, we can remarkably increase the magnetic moment of the hydrogen-absorbed PG system by 137 times. This would allow us to design a magnetic nanoswitch to manipulate the magnetic state of PG. We also obtained the scanning tunneling microscopy (STM) images for future experimental identification. Our findings show that the hydrogen atom absorbed on the PG system will have exciting applications in magnetic storage technology and next-generation electronic and spintronic nanodevices.

First-principle calculations reveal that the configuration system of hexagonal boron nitride (h-BN) monolayer with triangular vacancy can induce obvious magnetism, contrary to that of the nonmagnetic pristine boron nitride monolayer. Interestingly, the h-BN with boron atom vacancy (V B -BN) displays metallic behavior with a total magnetic moment being 0.46µ B per cell, while the h-BN with nitrogen atom vacancy (V N -BN) presents a half-metallic characteristic with a total magnetic moment being 1.0µ B per cell. Remarkably, piezoelectric stress coefficient e 11 of the V N -BN is about 1.5 times larger than that of pristine h-BN. Furthermore, piezoelectric strain coefficient d 11 (12.42 pm/V) of the V N -BN is 20 times larger than that of pristine h-BN and also one order of magnitude larger than the value for the h-MoS 2 monolayer, which is mainly due to the spin-down electronic state in the V N -BN system. Our study demonstrates that the nitrogen atom vacancies can be an efficient route to tailoring the magnetic and piezoelectric properties of h-BN monolayer, which have promising performances for potential applications in nano-electromechanical systems (NEMS) and nanoscale electronics devices.

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