Morphology engineering has been developed as one of the most widely used strategies for improving the performance of electrocatalysts. However, the harsh reaction conditions and cumbersome reaction steps during the nanomaterials synthesis still limit their industrial applications. Herein, one-dimensional (1D) novel-segmented PtTe porous nanochains (PNCs) were successfully synthesized by the template methods assisted by Pt autocatalytic reduction. The PtTe PNCs consist of consecutive mesoporous architectures that provide a large electrochemical surface area (ECSA) and abundant active sites to enhance methanol oxidation reaction (MOR). Furthermore, 1D nanostructure as a robust sustaining frame can maintain a high mass/charge transfer rate in a long-term durability test. After 2,000 cyclic voltammetry (CV) cycles, the ECSA value of PtTe PNCs remained as high as 44.47 m2·gPt–1, which was much larger than that of commercial Pt/C (3.95 m2·gPt–1). The high catalytic activity and durability of PtTe PNCs are also supported by CO stripping test and density functional theory calculation. This autocatalytic reduction-assisted synthesis provides new insights for designing efficient low-dimensional nanocatalysts.
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Formic acid oxidation (FAO) is a typical anode reaction in fuel cells that can be facilitated by modulating its direct and indirect reaction pathways. Herein, PtAu bimetallic nanoparticles loaded onto Co and N co-doping carbon nanoframes (CoNC NFs) were designed to improve the selectivity of the direct reaction pathway for efficient FAO. Based on these subtle nanomaterials, the influences of elemental composition and carbon-support materials on the two pathways of FAO were investigated in detail. The results of fuel cell tests verified that the appropriate amount of Au in PtAu/CoNC can promote a direct reaction pathway for FAO, which is crucial for enhancing the oxidation efficiency of formic acid. In particular, the obtained PtAu/CoNC with an optimal Pt/Au atomic ratio of 1:1 (PtAu/CoNC-3) manifests the best catalytic performance among the analogous obtained Pt-based electrocatalysts. The FAO mass activity of the PtAu/CoNC-3 sample reached 0.88 A·mgPt−1, which is 26.0 times higher than that of Pt/C. The results of first-principles calculation and CO stripping jointly demonstrate that the CO adsorption of PtAu/CoNC is considerably lower than that of Pt/CoNC and PtAu/C, which indicates that the synergistic effect of Pt, Au, and CoNC NFs is critical for the resistance of Pt to CO poisoning. This work is of great significance for a deeper understanding of the oxidation mechanism of formic acid and provides a feasible and promising strategy for enhancing the catalytic performance of the catalyst by improving the direct reaction pathway for FAO.
Pt-based magnetic nanocatalysts are one of the most suitable candidates for electrocatalytic materials due to their high electrochemistry activity and retrievability. Unfortunately, the inferior durability prevents them from being scaled-up, limiting their commercial applications. Herein, an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles (TONPs) by one-pot method. Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its antiferromagnetism. At low temperatures, Mn-PtCo TONPs are ferromagnetic, and the coercivity increases gradually with increasing Mn contents. At room temperature, the Mn-PtCo TONPs display superparamagnetic behavior, which is greatly helpful for industrial recycling. Mn doping can not only modify the electronic structure of PtCo TONPs but also enhance electrocatalytic performance for methanol oxidation reaction. The maximum specific activity of Mn-PtCo-3 reaches 8.1 A·m-2, 3.6 times of commercial Pt/C (2.2 A·m-2) and 1.4 times of PtCo TONPs (5.6 A·m-2), respectively. The mass activity decreases by only 30% after 2, 000 cycles, while it is 45% and 99% (nearly inactive) for PtCo TONPs and commercial Pt/C catalysts, respectively.