2D nanoconfinement technique enhances oxygen evolution performances

Prof. Zhang Tao’s group on the Ningbo Institute of Supplies Expertise and Engineering (NIMTE) of the Chinese language Academy of Sciences (CAS), in collaboration with Prof. Hou Yang from Zhejiang College and Prof. Xiao Jianping from the Dalian Institute of Chemical Physics of CAS, proposed a novel two-dimensional (2D) nanoconfinement technique to strongly improve the oxygen evolution response (OER) exercise of low-conductivity metal-organic frameworks (MOFs). Outcomes have been revealed in Nature Communications.

The event of high-efficiency electrocatalysts for the electrochemical conversion of water to generate environmentally pleasant and sustainable hydrogen vitality has drawn great consideration for many years.

Regardless of the essential position the OER performs in water splitting, OER on the anode requires a comparatively excessive thermodynamic potential to speed up water splitting kinetics. Because of the massive floor space, tunable porosity, numerous compositions and metallic facilities, MOFs have emerged as promising candidates for environment friendly OER electrocatalysts. Nevertheless, the intrinsically poor conductivity of essentially the most MOFs significantly impede their catalytic exercise.

To handle this difficulty, researchers at NIMTE proposed an electrochemical technique to confine MOFs between graphene multilayers by way of the two-electrode electrochemical system, thus endowing poorly conductive MOFs with strongly enhanced catalytic efficiency.

The as-prepared NiFe-MOF//G exhibits a remarkably low overpotential of 106 mV to achieve 10 mA cm^-2, surpassing the pristine NiFe-MOF in addition to different beforehand reported MOFs and their derivatives. Apart from, the NiFe-MOF//G electrode is very secure, which may retain the efficiency for greater than 150 h at 10 mA cm^-2 with out apparent exercise decay.

Notably, the outcomes of X-ray absorption spectroscopy experiments and density-functional principle calculations point out that the nanoconfinement from graphene multilayers optimizes the digital construction and catalysis heart of MOF supplies with the formation of extremely reactive NiO₆-FeO₅ distorted octahedral species in MOF construction. As well as, the nanoconfinement lowers limiting potential for water oxidation response.

The nanoconfinement technique may be utilized to different various MOFs with completely different buildings, drastically bettering their electrocatalytic actions. In the meantime, this work challenges the widespread conception of pristine MOFs as inert catalysts and divulges the nice utility potential of poorly conductive and even insulating MOFs in electrocatalysis functions.