Double Metal Diphosphide Pair Nanocages Coupled with P-Doped Carbon for Accelerated Oxygen and Hydrogen Evolution Kinetics

Abstract

Developing efficient and durable bifunctional transition metal phosphide (TMP) electrocatalysts is still a great challenge because of its relatively sluggish kinetics of oxygen evolution reaction (OER). Herein, we report a unique bimetallic diphosphide pair (FeP 2 −NiP 2 ) forming spherical nanocages encapsulated in P-doped carbon layers (FeP 2 − NiP 2 @PC) as advanced bifunctional electrocatalyst synthesized by a very facile phosphorization approach. The obtained FeP 2 −NiP 2 @PC electrocatalyst exhibits an outstanding OER activity with an ultralow overpotential of 248 mV in 1 M KOH and a low overpotential of 117 mV for HER in 0.5 M H 2 SO 4 (@10 mA•cm −2 ). Also it gives an exceptional longterm durability toward OER (60 h) and HER (20 h). Differently from the electrocatalysts as reported, after successive 3000 cycles CV acceleration, its overpotential decreases about 10 mV. Further investigation unveils that the electrochemical activation process boosts in situ phase transformation of oxides and phosphides to oxyhydroxides as the vital intermediates in FeP 2 −NiP 2 @PC during OER electrocatalysis. The direct observation of vital intermediates has been rarely reported on Fe/Ni-based phosphide electrocatalysts. Our exploration demonstrates an extraordinarily efficient and stable nonprecious TMP bifunctional electrocatalyst and provides a novel prospect to shed light on the intrinsic OER electrocatalytic behavior of Fe/Ni-based phosphide electrocatalysts.

Transition‐Metal Phosphides: Activity Origin, Energy‐Related Electrocatalysis Applications, and Synthetic Strategies

“…), [111,[143][144][145][146][147][148] hypophosphite (NH 4 H 2 PO 2 /NaH 2 PO 2 ) or PH 3 gas, [149][150][151][152][153][154][155][156][157][158] phosphate (NH 4 H 2 PO 4 , (NH 4 ) 2 HPO 4 , LiFePO 4 , etc. ), or phosphoric acid (H 3 PO 4 ), [91,[159][160][161][162][163][164][165][166] phytic acid, [167][168][169][170][171][172] red phosphorus, [46,126,[173][174][175][176][177][178] black phosphorus (BP) or phosphorene, [179][180][181][182][183] and other phosphorus, such as hexamethylene diamine tetra (methyl phosphonic acid) (HDTMPA), 1-hydroxyethylidene-1,1-phosphonic acid (HEDP), ionic liquid ([BMIM]•PF 6 ), ethylene diphosphonic acid, saccharomycetes/ Figure 6. a) SEM and b) T...…”

“…[137] Copyright 2020, Elsevier. Complicated exfoliation process [175][176][177][178][179] www.afm-journal.de www.advancedsciencenews.com…”

Facile Synthesis of Cobalt Oxide as an Efficient Electrocatalyst for Hydrogen Evolution Reaction

“…Because of their Pt-like catalytic behaviors for HER, well electrocatalysts originated from the most abundant elements (Co, Fe, Mo, Ni, Ti, W, and so on) has experienced rapid development over the past decade (Jung et al, 2014;Kuznetsov et al, 2019;Liu et al, 2020). Scientists design and develop various catalysts including transition metal oxides (CoO, Fe 3 O 4 , MoO 2 , TiO 2 , WO 2 ) (Park and Kolpak, 2019;Protsenko et al, 2019;Qian et al, 2019;Li L. et al, 2020;Li S. et al, 2020), metal sulfides (CoS, CuS, FeS 2 , MoS 2 , NiS 2 , V 3 S 4 , WS 2 ) (Li et al, 2018;Shi et al, 2019;Singh et al, 2019;Cao et al, 2020;Hao et al, 2020;Thangasamy et al, 2020), metal carbides (MoC 2 , WC) (Ji et al, 2018;Hussain et al, 2019), metal phosphides (CoP, NiP, FeP, WP, MoP) (Ojha et al, 2017;Zhang C. et al, 2018;Wang P. et al, 2019;Ji et al, 2020;Lin et al, 2020), metal selenides (CoSe 2 , MoSe 2 , NiSe 2 , WSe 2 ) (Wang et al, 2012(Wang et al, , 2020Chen et al, 2020;Nam et al, 2020) and metal boron (Huang et al, 2019;.…”

Ultrafast Activating Strategy to Significantly Enhance the Electrocatalysis of Commercial Carbon Cloth for Oxygen Evolution Reaction and Overall Water Splitting

“…Even so, the property of high‐cost and scarcity greatly limits the practical applications of precious metal‐based electrocatalyst . Therefore, more and more scientists have paid their attention to the non‐precious metal‐based materials such as transition metal compounds (including oxides, Chalcogenide, phosphides, hydroxides, layered double hydroxides (LDHs)) because of their high electrocatalytic activity and relatively low cost. Although many efforts have been made, the durability of metal‐based catalysts is still undesirable due to their inevitable side reaction with the electrolyte ions, which leads to the quench of electrochemically active sites.…”