MOF-Derived Iron-Cobalt Phosphide Nanoframe as Bifunctional Electrocatalysts for Overall Water Splitting

Transition metal phosphides(TMPs)have emerged as an alternative to precious metals as efficient and low-cost catalysts for water electrolysis.Elemental doping and morphology control are effective approaches to further improve the performance of TMPs.Herein,Fe-doped CoP nanoframes(Fe-CoP NFs)with specific open cage configuration were designed and synthesized.The unique nano-framework structured Fe-CoP material shows overpotentials of only 255 and 122 mV at 10 mA cm^(−2)for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER),respectively,overwhelming most transition metal phosphides.For overall water splitting,the cell voltage is 1.65 V for Fe-CoP NFs at a current density of 10 mA cm^(−2),much superior to what is observed for the classical nanocubic structures.Fe-CoP NFs show no activity degradation up to 100 h which contrasts sharply with the rapidly decaying performance of noble metal catalyst reference.The superior electrocatalytic performance of Fe-CoP NFs due to abundant accessible active sites,reduced kinetic energy barrier,and preferable*O-containing intermediate adsorption is demonstrated through experimental observations and theoretical calculations.Our findings could provide a potential method for the preparation of multifunctional material with hollow structures and offer more hopeful prospects for obtaining efficient earth-abundant catalysts for water splitting.

Enhancing the photoelectrochemical performance of p-silicon through TiO_(2)coating decorated with mesoporous MoS_(2)

MoS_(2)is a promising electrocatalyst for hydrogen evolution reaction and a good candidate for cocatalyst to enhance the photoelectrochemical(PEC)performance of Si-based photoelectrode in aqueous electrolytes.The main challenge lies in the optimization of the microstructure of MoS_(2),to improve its catalytic activity and to construct a mechanically and chemically stable cocatalyst/Si photocathode.In this paper,a highly-ordered mesoporous MoS_(2)was synthesized and decorated onto a TiO_(2)protected p-silicon substrate.An additional TiO_(2)necking was introduced to strengthen the bonding between the MoS_(2)particles and the TiO_(2)layer.This meso-MoS_(2)/TiO_(2)/p-Si hybrid photocathode exhibited significantly enhanced PEC performance,where an onset potential of+0.06 V(versus RHE)and a current density of-1.8 mA/cm^(2)at 0 V(versus RHE)with a Faradaic efficiency close to 100%was achieved in 0.5 mol/L H_(2)SO_(4).Additionally,this meso-MoS_(2)/TiO_(2)/p-Si photocathode showed an excellent PEC ability and durability in alkaline media.This paper provides a promising strategy to enhance and protect the photocathode through high-performance surface cocatalysts.