No abstract

Ethanol, as a sustainable biomass fuel, is endowed with the merits of theoretically high energy density and environmental friendliness yet suffers from sluggish kinetics and low selectivity toward the desired complete electrooxidation (C1 pathway). Here, the localized surface plasmon resonance (LSPR) effect is explored as a manipulating knob to boost electrocatalytic ethanol oxidation reaction in alkaline media under ambient conditions by appropriate visible light. Under illumination, Au@Pt nanoparticles with plasmonic core and active shell exhibit concurrently higher activity (from 2.30 to 4.05 A mg Pt −1 at 0.8 V vs RHE) and C1 selectivity (from 9 to 38% at 0.8 V). In situ attenuated total reflection−surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) provides a molecular level insight into the LSPR promoted C−C bond cleavage and the subsequent CO oxidation. This work not only extends the methodology hyphenating plasmonic electrocatalysis and in situ surface IR spectroscopy but also presents a promising approach for tuning complex reaction pathways.

The dissolution of M in currently popular Pt–M alloy catalysts (M = Co, Ni, and Fe) during the oxygen reduction reaction (ORR) may deter their wide application in proton exchange membrane fuel cells (PEMFCs). In this work, interstitial B-doping in the Pt lattice is instead used to design a durable and active ORR catalyst, by taking advantage of its unique regulation of the electronic structure of surface Pt sites. 3 nm Pt–B nanoparticles on carbon black (Pt–B/C) are obtained using dimethylamine borane (DMAB) as a reductant and the B source in a mixed H2O–ethylene glycol precursor solution. The formation of the B-doped Pt catalyst is verified by inductively coupled plasma-atomic emission spectrometry, X-ray diffractometry, and spherical aberration-corrected scanning transmission electron microscopy. Both half-cell and single-cell tests indicate that the as-synthesized Pt–B/C catalyst outperforms the commercial Pt/C­(com) in terms of activity and durability. In particular, the Pt–B/C-based PEMFC exhibits an initial maximum power density 1.24 times as high as the Pt/C­(com)-based one under otherwise same conditions, with a 15% decay for the former versus a 45% decay for the latter after 30 000 cycles of the accelerated degradation test (ADT). Comparative DFT calculations on B-doped and undoped Pt(111) surfaces reveal that the lowered Pt d-band center and the strong interaction of Pt–B bonding weaken the binding of OH and O species to surface Pt sites and lessen oxidative disruption of surface Pt atoms. This interstitial metalloid doping in conjunction with the simple and scalable synthesis protocol enables the Pt–B/C to be a competitive ORR catalyst for the PEMFCs.