Electronic Structure Effect of PtCo Alloy with Adjustable Compositions for Efficient Methanol Electrooxidation

Abstract

Various efficient strategies have been developed to overcome the anodic electrocatalyst issue of methanol-based fuel cells owing to their complicated methanol electrooxidation mechanism. In this work, PtCo nanoparticles with adjustable compositions supported on multiwalled carbon nanotubes (Pt 1 Co x /MWCNTs) through the adsorbing−coating−annealing− etching route were synthesized. Compared with the Pt/C catalyst, Pt 1 Co 3 /MWCNTs exhibit better electrocatalytic MOR activity in both activity and durability. Notably, the electrochemical mass and specific activity of the as-prepared catalyst are 1.04 mA μg −1 Pt and 2.18 mA cm −2 , respectively, which are higher than those of the Pt/ C catalyst. Moreover, the as-prepared sample revealed lower onset potential during the CO stripping test. Furthermore, the Pt 1 Co 3 / MWCNTs possess a lower current density decrease rate in chronoamperometry and cyclic durability tests. The enhancement of activity and stability of Pt 1 Co 3 /MWCNTs could be ascribed to their ordered morphological structure, the electronic interaction between MWCNTs and PtCo nanoparticles, and the suitable electronic structure effect between Pt/Co ratios. The concept of the catalyst design in this study offers a different guideline for constructing the novel methanol electrooxidation catalyst, which will accelerate the widespread fuel cell practical application.

Benzene-Linked Polymeric Carbon Nitride for Enhanced Photocatalytic Hydrogen Production

“…If inserting benzene ring resulted in a heterocyclic ring is missed in the structure, some N–(C) 3 linkages may miss and introduce certain defects, the content of N in N–(C) 3 should dwindled to certain degree. Our findings deviate from those reported data, which have overstated the ratio of N–(C) 3 to sp 2 N in in CN–C, due to casual fitting for XPS spectra. − A higher ratio of N–(C) 3 indicates a higher degree of polymerization for PCN . If the ratio of sp 2 N in CN–C to N–(C) 3 were to reach 1.29, it implies the insertion of two benzene rings in three tri- s -triazine, contradicting their proposed structure for benzene-doped CNs.…”

“…However, the ratio of N–(C) 3 to sp 2 (C–NC) was calculated in an invalid way for the casual XPS spectra fitting. N 1s missed the peak of C–NH for benzene ring doped CN, while N 1s fitted the XPS spectra with unequal fwhm (full width at half maxim) . Yuan et al reported that benzene ring embedded in carbon nitride as electron acceptor .…”

“…Recently, several works reported that inserting a benzene ring in the PCN framework enhanced photocatalytic performance in hydrogen evolution or pollutant degradation. Even though it was a simple structure modification, there were some contradictions in the proposed structures and experimental result analysis. − Jia et al reported that benzene ring embedded in PCN decreased the bandgap . They proposed a molecular structure, where a heterocyclic ring is missed, and another one is replaced by a benzene ring in PCN structure.…”

Tuning the CO2 Reduction Activity of Graphitic Carbon Nitride via the Capping-Agent-Free Involvement of Ag Nanocrystals

“…Overusing fossil fuels worldwide has sparked significant concern about environmental crises and climate change resulting from CO 2 emissions. − To effectively address these challenges, the conversion of CO 2 into useful chemicals (such as CO, CH 4 , C 2 H 4 , and C 2 H 6 ) using sustainable and clean electronics under ambient conditions is of anxious demand. − However, the high overpotential, poor selectivity, and inferior faradaic efficiency (FE) for the target products, along with competition from the hydrogen evolution reaction (HER), are the main obstacles that significantly hinder the current large-scale application of the CO 2 reduction reaction (CRR). − Therefore, it is of great importance to explore an advanced CRR electrocatalyst with high selectivity and activity at a lower overpotential. , …”

Theoretical Exploration of Anchoring Type Effects of C2N Nanosheet-Supported Nickel Atoms for Urea Electrooxidation

“…The prerequisite for the practical application of this type of catalyst is to stably scatter metal atoms on supports that can strongly interact with the metal atoms to prevent their possible aggregation. 2D materials like graphene, boron nitrides, and transition metal dichalcogenides with unique physiochemical properties were widely investigated as substrates for metal atoms. − However, metal atoms tend to diffuse and agglomerate on these substrates . Introducing vacancies and holes can solve this issue, but precisely carving and holding vacancies and holes are extremely difficult in large-scale applications .…”