Improving electrochemical activity of PtRu/SnO_2/C catalyst by reduction treatment and alkaline etching

PtRu/SnO/C catalyst was prepared in a polyol process, followed by reduction treatment and alkaline etching. X-ray diffraction, transmission electron microscope with energy dispersive spectrometer and Xray photoelectron spectroscopy were used to characterize the morphology, structure and composition of the catalysts. CO and methanol electro-oxidation activities of the catalysts were evaluated by CO stripping voltammetry, cyclic voltammetry and chronoamperometry measurements. Reduction treatment of the prepared PtRuSnO/C catalyst in a polyol process induced the enrichment of Sn on the surface, inhibiting methanol dissolution and CO adsorption on Pt. Alkaline etching removed Sn or SnOand thus exposed PtRu on the surface, resulting in enhanced activities for CO and methanol electro-oxidation due to the synergy effects of PtRu on the surface and Sn species beneath.

Insight into the hydrogen oxidation electrocatalytic performance enhancement on Ni via oxophilic regulation of MoO_(2)

Exploring platinum-group-metal(PGM)free electrocatalysts for hydrogen oxidation reaction(HOR)in alkaline media is essential to the progress of anion exchange membrane fuel cells(AEMFCs).In this work,a Ni/MoO_(2) heterostructure catalyst with comparable HOR activity in alkaline electrolyte with PGM catalyst was prepared by a simple hydrothermal-reduction method.Remarkably,the Ni/MoO_(2) presents a mass kinetic current density of 38.5 mA mgNi^(-1) at the overpotential of 50 mV,which is higher than that of the best PGM free HOR catalyst reported by far.Moreover,the HOR performance of Ni/MoO_(2) under 100 ppm CO shows negligible fading,together with the superior durability,render it significant potential for application in AEMFCs.A particular mechanistic study indicates that the excellent HOR performance is ascribed to the accelerated Volmer step by the incorporation of MoO_(2).The function of MoO_(2) was further confirmed by CO striping experiment on Pt/C-MoO_(2) that MoO_(2) can facilitated OH adsorption thus accelerate the HOR process.On account of the high performance and low cost,the Ni/MoO_(2) electrocatalyst encourages the establishment of high performance PGM free catalyst and shows significant potential for application in AEMFCs.

Porous Pt nanoframes decorated with Bi(OH)3 as highly efficient and stable electrocatalyst for ethanol oxidation reaction

High-quality Pt-based catalysts are highly desirable for ethanol oxidation reaction(EOR),which is of critical importance for the commercial applications of direct ethanol fuel cells(DEFCs).However,most of the Pt-based catalysts have suffered from high cost and low operation durability.Herein a two-step method has been developed to synthesize porous Pt nanoframes decorated with Bi(OH)3,which show excellent catalytic activity and operation durability in both alkaline and acidic media.For example,the nanoframes show a mass activity of 6.87 A·mgPt−1 in alkaline media,which is 13.5-fold higher than that of commercial Pt/C.More importantly,the catalyst can be reactivated simply,which shows negligible activity loss after running for 180,000 s.Further in situ attenuated total reflection-infrared(ATR-IR)absorption spectroscopy and CO-stripping experiments indicate that surface Bi(OH)3 species can greatly facilitate the formation of adsorbed OH species and subsequently remove carbonaceous poison,resulting in a significantly enhanced stability towards EOR.This work may favor the tailoring of desired electrocatalysts with high activity and durability for future commercial application of DEFCs.

Synergistic combination of Pd nanosheets and porous Bi(OH)_(3) boosts activity and durability for ethanol oxidation reaction

Highly active and durable Pd-based electrocatalysts for ethanol oxidation reaction(EOR)play a crucial role in the commercialization of direct ethanol fuel cells(DEFCs).However,the poisonous intermediates(especially adsorbed CO species(COad))formed during the EOR process can easily adsorb and block the active sites on Pd electrodes,which in turn limits the catalytic efficiency.Hence,we present a series of Pd-based composites with a strong coupling interface consisting of Pd nanosheets and amorphous Bi(OH)_(3)species.The incorporation of Bi(OH)3 can induce an electron-rich state adjacent to the Pd sites and effectively separate the Pd ensemble,leading to excellent CO tolerance.The optimal Pd-Bi(OH)_(3)NSs catalyst manifests a mass activity of 2.2 A·mgPd^(-1),which is 5.7 and 2.0 times higher than that of Pd NSs and commercial Pd/C catalyst,respectively.Further CO-stripping experiments and CO-DRIFTS tests confirm the excellent CO tolerance on Pd-Bi(OH)3 NSs electrode,leading to the enhanced EOR durability.

Dual synergetic catalytic effects boost hydrogen electric oxidation performance of Pd/W_(18)O_(49)

Developing anode catalysts of substantially enhanced activity for hydrogen oxidation reaction(HOR)and anti-CO poisoning performance is of great importance for the application of proton exchange membrane fuel cells(PEMFCs).Herein,we report Pd cluster in situ decorated urchin-like W_(18)O_(49)(WO_(2.72))electrocatalysts by a photo-reduction method for high performance HOR.The synthesized Pd-WO_(2.72)-L composite of low loading amount of 0.44 wt.%Pd by Xenon light reduction exhibits markedly high HOR catalytic activity and stability in 0.5 M H_(2)SO_(4),and the specific HOR current density and mass activity of Pd-WO_(2.72)-L are~1.5 and~80 times those of 20 wt.%Pt/C catalyst,respectively.Moreover,excellent anti-CO poisoning ability has also been obtained.The excellent HOR activity and anti-CO poisoning performance of Pd-WO_(2.72)-L have been discussed mainly in terms of the dual synergetic catalytic effects between Pd and WO_(2.72):Pd activation to Pd^(δ+)by the electron transfer from Pd to W promotes the hydrogen adsorption and activation to H*species,which results in largely elevated HOR activity;Pd degradation due to the CO poisoning is effectively prevented by WO_(2.72),which is responsible for the excellent CO-tolerance performance.