ABSTRACT
Efficient and inexpensive electrocatalysts play an important role in the hydrogen evolution reaction (HER) of electrolytic water splitting. Herein, Ni2P-MoC/coal-based carbon fiber (Ni2P-MoC/C-CF) self-supporting catalysts were obtained by low-temperature phosphorization and high-temperature carbonization. The Mo source and oxidized coal were uniformly dispersed in the carbon support by electrospinning technology. A precursor of Ni was introduced by the impregnation method. The synergistic effect of MoC and Ni2P may reduce the strong hydrogen adsorption capacity of pure MoC and provide a fast hydrogen release process. In addition, the C-CFs prepared by electrospinning can not only prevent the agglomeration of MoC and Ni2P particles at a high temperature but also provide a self-supporting support for the catalyst. As a result, the catalytic performance of the HER was improved greatly, and a low overpotential of 112 mV at 10 mA cm-2 was exhibited stably by the Ni2P-MoC/C-CFs. This work not only converts coal into coal-based carbon materials but also provides a feasible pathway for the rational design of large-scale molded hydrogen electrocatalysts.
ABSTRACT
As an environmentally friendly energy technology, direct methanol fuel cells (DMFCs) meet the needs of sustainable development. Herein, novel dicyanamide anion-based (N(CN)2-) ionic liquid (IL)-functionalized reduced graphene oxide (rGO)-supported Pt catalysts are synthesized via a facile one-pot room temperature reduction method, which show a boost in methanol oxidation performance compared with Pt/rGO. The mass activities of the as-prepared Pt/emimN(CN)2/rGO (863.6 mA mg-1Pt) and Pt/epyN(CN)2/rGO (524.9 mA mg-1Pt) are about five and three times higher than that of Pt/rGO (178.6 mA mg-1Pt), and about six and four times higher than that of Pt/C (140.2 mA mg-1Pt), respectively. The participation of ILs significantly improves the CO poisoning resistance, stability, and activity for methanol oxidation of catalysts. The relationship between the structures and conductivities of diverse ILs and the performance of Pt catalysts are studied systematically. These findings may offer a promising prospect of ILs in DMFCs.
ABSTRACT
It is of prime importance to develop anode electrocatalysts for direct methanol fuel cells (DMFCs) with good performance, which is critical for their commercial applications. Metal-organic framework (MOF)-derived carbon materials are extensively developed as supports of catalysts. Herein, Co embedded nitrogen-doped carbon nanotube hollow porous carbon (Co-NCNT-HPC) derived from MOFs have been fabricated, which were synthesized by pyrolyzing at an optimized temperature of 800 °C using ZIF-8@ZIF-67 as a precursor. The presence of ZIF-8@ZIF-67 ensures the doping of nitrogen and the large specific surface area of the support materials at high temperatures. A Pt/Co-NCNT-HPC800 sample, which was synthesized using Co-NCNT-HPC800 as a support, showed an enhanced mass activity of 416.2 mA mg-1Pt for methanol oxidation reaction (MOR), and the onset potential of COad oxidation of 0.51 V, which shifted negatively about 0.13 V compared with Pt/C (20%). Moreover, the Pt/Co-NCNT-HPC800 sample exhibits high stability. This work provides a facile strategy for MOF-derived carbon materials to construct advanced electrocatalysts for MOR.
ABSTRACT
Development of a Pd-based catalyst with highly active and durable properties for formic acid oxidation reaction at the anode remains an important matter of interest in the research community. Herein, we have designed novel coal-based carbon fibers (Coal-CFs) with dicyandiamide (DCD) as nitrogen (N) source, triphenylphosphine (TPP) as phosphorus (P) source dual-doped to support Pd catalysts (Pd/NP-Coal-CFs(DCD/TPP)), which exhibit superior catalytic performance toward formic acid oxidation reaction. Mass activity of formic acid oxidation of Pd/NP-Coal-CFs(DCD/TPP) catalyst is 536.6 mA·mg-1Pd, which is 2.5 times higher than that of Pd/Coal-CFs catalyst. The higher specific surface areas, exclusive electron transport path, and the high synergistic interaction of N and P are the favorable phenomena for catalytic performance. The addition of coal not only increases the abundant defects sites but also makes the utilization of coal with high added value. This N and P dual-doped catalyst inspires an idea for promoting applications in practical fuel cells.