Engineering and understanding of synergistic effects in the interfaces of rGO-CNTs/PtPd nanocomposite revealed fast electro-oxidation of methanol

Recent development and applications of differential electrochemical mass spectrometry in emerging energy conversion and storage solutions

Electrochemical energy conversion and storage are playing an increasingly important role in shaping the sustainable future. Differential electrochemical mass spectrometry (DEMS) offers an operando and cost-effective tool to monitor the evolution of gaseous/volatile intermediates and products during these processes. It can deliver potential-, time-, mass- and space-resolved signals which facilitate the understanding of reaction kinetics. In this review, we show the latest developments and applications of DEMS in various energy-related electrochemical reactions from three distinct perspectives. (I) What is DEMS addresses the working principles and key components of DEMS, highlighting the new and distinct instrumental configurations for different applications. (II) How to use DEMS tackles practical matters including the electrochemical test protocols, quantification of both potential and mass signals, and error analysis. (III) Where to apply DEMS is the focus of this review, dealing with concrete examples and unique values of DEMS studies in both energy conversion applications (CO2 reduction, water electrolysis, carbon corrosion, N-related catalysis, electrosynthesis, fuel cells, photo-electrocatalysis and beyond) and energy storage applications (Li-ion batteries and beyond, metal-air batteries, supercapacitors and flow batteries). The recent development of DEMS-hyphenated techniques and the outlook of the DEMS technique are discussed at the end. As DEMS celebrates its 40th anniversary in 2024, we hope this review can offer electrochemistry researchers a comprehensive understanding of the latest developments of DEMS and will inspire them to tackle emerging scientific questions using DEMS.

N-Doped Carbon Nanotube Shell Encapsulating the NiFe Metal Core for Enhanced Catalytic Stability in Methanol Oxidation Reaction by the Structural Cooperation Mechanism

Exploitation of high-efficiency catalysts toward methanol oxidation is a pivotal step to promote the commercialization of direct methanol fuel cells. Herein, a strategy is demonstrated to prepare nitrogen-doped carbon nanotubes with NiFe metal particles (NiFe@N-CNT) as the carrier material of Pt nanoparticles. Combining SEM and TEM, NiFe metal particles are fully encapsulated in N-CNTs, and they form the metal core and carbon nanotube shell structure based on the structural cooperation mechanism. Surprisingly, the as-prepared Pt/NiFe@N-CNT catalyst shows superior catalytic activity (1023 mA mg^-1_Pt) compared to commercial Pt/C (392 mA mg^-1_Pt), Pt/Ni@N-CNT (331 mA mg^-1_Pt), and Pt/Fe@N-CNT (592 mA mg^-1_Pt). After 1000 cycles, Pt/NiFe@N-CNT maintains the optimal catalytic activity (588 mA mg^-1_Pt), and its mass activity loss is 42.5%, which is better than those of commercial Pt/C (64.0%), Pt/Ni@N-CNT (67.7%), and Pt/Fe@N-CNT (59.6%) catalysts, indicating that the Pt/NiFe@N-CNT catalyst achieves excellent catalytic activity and stability, which stems chiefly from the homodispersed Pt nanoparticles and the generation of the metal core-carbon nanotube shell based on the structural cooperation mechanism. This study reports the facile construction of a metal core-carbon nanotube shell structure, which intrinsically ameliorates structural collapse of carrier material, thereby improving the catalytic stability of the Pt-based catalyst and broadening the view for design of other desire catalysts in methanol oxidation.

High-efficiency methanol oxidation electrocatalysts realized by ultrathin PtRuM-O (M = Ni, Fe, Co) nanosheets

A general method for controlling the synthesis of a class of ultrathin PtRuM-O (M = Ni, Fe, Co) NSs is reported for the first time. By optimizing the metal ratio, the Pt₇RuNi₂-O NS catalyst is found to have the highest electrocatalytic activity (mass activity, 3.57 A mg_Pt^-1) for the MOR among PtRuM-O NSs and PtRu-O NSs, which is 10.5 times higher than that of commercial Pt/C (0.34 A mg_Pt^-1). And the Pt₇RuNi₂-O NSs also have better stability and CO anti-poisoning properties in the prepared materials. In addition, the ultrathin Pt₇RuNi₂-O NS catalyst also shows the highest performance among reported Pt-based catalysts for the MOR in acidic medium.

Efficient polyalcohol oxidation electrocatalysts enabled by PtM (M = Fe, Co, and Ni) nanocubes surrounded by (200) crystal facets

Due to the high-density (200) crystal planes and abundant active sites, cubic platinum nanomaterials have become outstanding electrocatalysts in promoting fuel cell reactions. However, because of the fact that the facet-controlled synthesis is difficult, it is still a grand challenge to synthesize a sequence of Pt-based nanocubes via a universal method. Herein, we report a general and simple eco-friendly solvothermal method to prepare (200)-enclosed PtM nanocubes. Different from the other nanomaterials, nanocubes are conducive to mass transfer. Moreover, the synergistic and electronic effects between M and Pt are profitable to improve the utilization of precious metals. We used (200)-encapsulated nanocrystals to evaluate their electrocatalytic performance towards glycerol and ethylene glycol oxidation reactions in an alkaline medium. In particular, Pt4Co nanocubes showed superior mass activities in glycerol and ethylene glycol oxidation reactions, which are 6.2- and 5.0-fold higher than those obtained for commercial Pt/C catalysts, respectively. Meanwhile, Pt4M catalysts manifested excellent stability in the endurance test, which is attributed to the alloying effect promoting the electrooxidation of intermediates. Our study provides an ideal method for the construction of Pt-based bimetallic nanocubes, which can be used for anode reactions of polyol fuel cells and beyond.

Platinum–palladium alloy nanotetrahedra with tuneable lattice-strain for enhanced intrinsic activity

Understanding how to regulate lattice strain of PtPd NTDs and the correlation of PtPd NTDs between the compositions, tuneable lattice strain and the electrocatalytic properties.