Carbon Nanotubes Decorated with CoP Nanocrystals: A Highly Active Non‐Noble‐Metal Nanohybrid Electrocatalyst for Hydrogen Evolution

Abstract

The development of effective and inexpensive hydrogen evolution reaction (HER) electrocatalysts for future renewable energy systems is highly desired. The strongly acidic conditions in proton exchange membranes create a need for acid-stable HER catalysts. A nanohybrid that consists of carbon nanotubes decorated with CoP nanocrystals (CoP/ CNT) was prepared by the low-temperature phosphidation of a Co 3 O 4 /CNT precursor. As a novel non-noble-metal HER catalyst operating in acidic electrolytes, the nanohybrid exhibits an onset overpotential of as low as 40 mV, a Tafel slope of 54 mV dec À1 , an exchange current density of 0.13 mA cm À2 , and a Faradaic efficiency of nearly 100 %. This catalyst maintains its catalytic activity for at least 18 hours and only requires overpotentials of 70 and 122 mV to attain current densities of 2 and 10 mA cm À2 , respectively.

Electrocatalysts for hydrogen oxidation and evolution reactions

“…The overpotential required to achieve a current density of 20 mA cm −2 is reduced to 85 mV at a catalyst loading of 3 mg cm −2 . Sun and co-authors [65] decorated carbon nanotubes with CoP nanoparticles via low-temperature phosphidation of Co 3 O 4 /CNT. The particle size is about 2−3 nm.…”

Exploration of Zr–Metal–Organic Framework as Efficient Photocatalyst for Hydrogen Production

“…Recently, Yu and coworkers have made a systematic analysis of the heterojunction photocatalysts, which provides an important reference for the subsequent photocatalytic research [23]. Furthermore, some phosphorus such as CoP [24,25], Ni 2 P [26], Cu 3 P [27], and MoP [28] have been employed for H 2 production. Especially, metal-organic frameworks (MOFs) with outstanding characteristics have attracted tremendous attention as catalysts or catalyst carriers for photocatalytic water splitting in the past few years [29][30][31].…”

Analysis of Trends and Emerging Technologies in Water Electrolysis Research Based on a Computational Method: A Comparison with Fuel Cell Research

“…This topic could dominate after fundamental studies, such as those in clusters III-A and III-B, are completed. Cluster III-D "Carbide, phosphide, sulfide, and selenide for HER" does not focus on oxides, but on composites of transition metals (Co, Ni, Mo, and W) and typical elements (C, P, S, and Se) [62][63][64][65][66][67]. The number of publications in this cluster exponentially increased from 2013, thus cluster III-D covers a research area that receives great interest.…”

“…Notably, Ni 5 P 4 is stable, even under strongly acidic conditions (1M H 2 SO 4 ), and exhibits high catalytic activity despite that it does not contain a noble metal [76,77]. In addition, CoP has also been reported as an acid-stable catalyst for HER and OER [62]. Although the current density and duration in their stability tests are restricted, these materials have the potential to become more stable.…”