Processable Surface Modification of Nickel‐Heteroatom (N, S) Bridge Sites for Promoted Alkaline Hydrogen Evolution

Abstract

Nickel-heteroatoms bridge sites are important reaction descriptors for many catalytic and electrochemical processes.Herein we report the controllable surface modification of nickel-nitrogen (NiÀN) bridge sites on metallic Ni particles via asimplified vapor-assisted treatment approach. Xray absorption spectroscopy( XAS) and Operando Raman spectroscopyv erifies the interaction between Ni and surfaceanchored N, whichl eads to distorted Ni lattice structure with improved wettability.T he NiÀNb ridge sites with appropriate Ncoveragelevel plays acritical role in the enhanced hydrogen evolution reaction (HER) and the optimizede lectrode (NiÀ N 0.19 )has demonstrated superior HER performances with low overpotential merely of 42 mV for achieving ac urrent density of 10 mA cm À2 ,a sw ell as favorable reaction kinetics and excellent durability in alkaline electrolyte.D FT calculations revealed that the appropriate N-coverage level can lead to the most favorable DG H* kinetics for both adsorption of H* and release of H 2 ,w hile high Nc overage (NiÀN 0.59 )r esults in weaker H* adsorption, thus ad ecreased HER activity, corresponding well to our experimental observations.Furthermore,t his generic synthetic approach can also be applied to prepare S-modified Ni HER catalyst by generating hydrogen sulfide vapor.Nickel is an ideal non-noble metal catalyst for many key industrial applications ranging from water electrolysis,chloralkali reactions,tophotoelectrochemical water splitting. [1] To al arge extent, the performance of Ni is determined by the chemical structure of outer or sublayer atoms around Ni particles that directly interact with reactant species.C onsequently,s urface modification of Ni represents an important strategy to tune its chemical and structural properties for achieving enhanced catalytic performances.T raditionally,N i has been modified with heteroatoms such as Oand Stoform corresponding oxides and sulfides;h owever, their performances are still far from satisfactory.Most recently,significant interest has been aroused to heteroatoms beyond Oand S, for example,Natoms.Both theoretical and experimental studies revealed that the as-formed Ni À Nb ridge sites can adsorb various reagent species such as hydroxyl, water, and carbon dioxide,a nd the charge transfer between them is usually the rate-determining step (RDS) of many reactions.For example, Bao and co-workers reported the formation of molecular Ni À Nc omplex that demonstrated excellent performances for catalytic CO 2 reduction reactions. [2] Antonietti and co-workers fabricated 3D Ni nitride on Ni foam for HER in alkaline media. [3] Despite these developments,s everal key challenges remain in this research direction:( i) Ther ational manipulation of Ni À Nb ridges sites with different Nc overage on Ni surfaces for satisfying different catalytic reactions to achieve optimal performances.( ii)M ost synthetic procedures for generating NiÀNbridges sites,like pyrolysis [2,3] and ammonia annealing, [4] require harsh and complicated experimental conditions an...

Implanting Ni-O-VOx sites into Cu-doped Ni for low-overpotential alkaline hydrogen evolution

“…As shown in Supplementary Fig. 4, the XRD patterns for Ni and Ni(Cu) are all crystalline with three main diffraction peaks at 2θ = 44.44°, 51.26°, and 76.35°, assigning to (111), (200), and (220) planes of face-centered cubic (fcc) Ni (JCPDS, No.70-0989) 17,26 . For Ni(Cu), the shoulder peaks appear at the base of Ni(111) and (200), indicating the partial formation of NiCu alloy.…”

“…Performance study revealed that Cr 2 O 3 coating was essential for maintaining the core NiO/Ni active sites from oxidation and aggregation. Recently, we demonstrated that Nmodified Ni catalysts with appropriate N coverage level plays a critical role towards electrochemical water splitting 17 . Experimental and density functional theory (DFT) calculations revealed that an appropriate N-coverage level can lead to favorable kinetics for H* adsorption and fast release of H 2 , and consequently enhanced activity and stability.…”

Boosting Alkaline Hydrogen Evolution Electrocatalysis over Metallic Nickel Sites through Synergistic Coupling with Vanadium Sesquioxide

“…To evaluatet he HER performance, we examined the activity of Ni-V 2 O 3 /NF by using at hree-electrode system in H 2 -saturated 1.0 m KOH. For comparison, Ni/NF,b lank NF,a nd commercial Pt/C (20 wt %P to nV ulcan carbonb lack) on glassy carbon www.chemsuschem.org À10 mA cm À2 at an extremelyl ow overpotential of only 25 mV (h 10 = 25 mV;F igure 4b), which was even lower than the value for the Pt/C catalyst( h 10 = 27 mV) and previously reported HER electrocatalysts, such as Ni, Zn-dual doped CoO NR (h 10 = 53 mV), [38] PtNi-O/C (h 10 = 39.8 mV), [39] Ni NPs/Ni-NC (h 10 = 147 mV), [40] Co/PCN (h 10 = 89 mV), [37] Ni-N 0.19 (h 10 = 42 mV) [41] and NiFeRu-LDH(h 10 = 29 mV) [42] (more comparisons are given in Table S1). In sharp contrast, Ni/NF (h 10 = 198 mV) and blank NF (h 10 = 295 mV) showedm uch largerH ER overpotentials.…”

“…Ni‐V 2 O 3 /NF exhibited nearly zero onset HER overpotential (Figure a). Moreover, the Ni‐V 2 O 3 /NF sample reached a current density of −10 mA cm −2 at an extremely low overpotential of only 25 mV ( η 10 =25 mV; Figure b), which was even lower than the value for the Pt/C catalyst ( η 10 =27 mV) and previously reported HER electrocatalysts, such as Ni, Zn‐dual doped CoO NR ( η 10 =53 mV), PtNi‐O/C ( η 10 =39.8 mV), Ni NPs/Ni‐NC ( η 10 =147 mV), Co/PCN ( η 10 =89 mV), Ni‐N 0.19 ( η 10 =42 mV) and NiFeRu‐LDH( η 10 =29 mV) (more comparisons are given in Table S1). In sharp contrast, Ni/NF ( η 10 =198 mV) and blank NF ( η 10 =295 mV) showed much larger HER overpotentials.…”

Molybdenum Sulfide Nanosheets Coupled with Ni2P Hollow Microspheres as an Efficient Electrocatalyst for Hydrogen Generation over a Wide pH Range Mediated by a 3D/2D Interface

“…[10] Thus, it is necessary to explore cost-effective and abundant non-noble metal-based catalysts for HER. [11] Recently, transition metal-based catalyst [12] and its nitrides, [13,14] phosphatides, [15][16][17][18] carbides [19,20] and sulfides [21,22] have been explored as efficient HER electrocatalysts. In particular, MoS 2 has been reported remarkable catalytic performance towards HER.…”