Lattice Strained B‐Doped Ni Nanoparticles for Efficient Electrochemical H₂O₂ Synthesis

Abstract

Surface strains are necessary to optimize the oxygen adsorption energy during the oxygen reduction reaction (ORR) in the four‐electron process, but the surface strains regulation for ORR in the two‐electron process to produce hydrogen peroxide (H2O2) is rarely studied. Herein, it is reported that the tensile strained B‐doped Ni nanoparticles on carbon support (Ni‐B@BNC) could enhance the adsorption of O2, stabilize OO bond, and boost the electrocatalytic ORR to H2O2. Moreover, the Ni‐B@BNC catalysts exhibit volcano‐type activity for electrocatalytic ORR to H2O2 as a function of the strain intensity, which is controlled by B content. Among them, Ni4‐B1@BNC exhibits the highest H2O2 selectivity of over 86%, H2O2 yield of 128.5 mmol h–1 g–1, and Faraday efficiency of 94.9% at 0.6 V vs reversible hydrogen electrode as well as durable stability after successive cycling, being one of the state‐of‐the‐art electrocatalysts for two‐electron ORR. The density functional theory calculations reveal that tensile strain introduced by doping B into Ni nanoparticles could decrease the state density of Ni‐3d orbital and optimize the binding energy of OOH* during ORR. A new direction is provided here for the design of highly active and stable catalysts for potential H2O2 production and beyond.

Lattice‐Strained Metallic Aerogels as Efficient and Anti‐Poisoning Electrocatalysts for Oxygen Reduction Reaction

“…proved that the compressive strain between core and shell regions could cause a downshift of the d‐band center of Pd sites, thus achieving high ORR activity [20] . Moreover, we also found that the tensile‐strained B‐doped Ni nanoparticles on carbon support (Ni‐B@BNC) could enhance the adsorption of O 2 , stabilize O−O bond, and boost the electrocatalytic ORR to H 2 O 2 [21] . Besides, as a kind of three‐dimensional (3D) porous materials, metallic aerogels (MAs) have attracted much attention by reason of the large specific surface area and abundant interconnected channels.…”

“…[20] Moreover, we also found that the tensile-strained B-doped Ni nanoparticles on carbon support (Ni-B@BNC) could enhance the adsorption of O 2 , stabilize OÀ O bond, and boost the electrocatalytic ORR to H 2 O 2 . [21] Besides, as a kind of three-dimensional (3D) porous materials, metallic aerogels (MAs) have attracted much attention by reason of the large specific surface area and abundant interconnected channels. Thanks to the intrinsic physicochemical characteristics, MAs possess copious active sites, excellent structural durability and plentiful mass/electron transfer channels, endowing their widely applications in diverse electrocatalytic reactions.…”

Lewis Acid Site Al-Promoted CoAl2O4/CoO Electrocatalyst for Efficient Electrochemical Production of H2O2 toward On-Site Pollutant Degradation

“…The projected densities of states (PDOS) of the d -band in the Co atom of CoAl 2 O 4 and Co 3 O 4 are shown in Figure S12. The portion of CoAl 2 O 4 that occupies the d orbital (especially d z 2 ) is closer to the Fermi level than Co 3 O 4 . , The d z 2 orbital of cobalt can overlap with the p z orbital of oxygen to form a strong σ-bond, which is attributed to the spatial configuration of the d orbitals. , Therefore, the σ bond contributed by the Co d z 2 orbital of CoAl 2 O 4 improves the adsorption and desorption of OOH* and carries out effective 2-electron reduction. The densities of states shown in Figure d for CoAl 2 O 4 and Co 3 O 4 indicate that the Lewis acid site Al changes the density of states of the Co-3d orbital near the Fermi level. ,, Compared with the Co 3 O 4 (−3.06 eV), the d-band center of CoAl 2 O 4 (−2.78 eV) is closer to the Fermi level, which may enhance the adsorption of O 2 …”

“…Figure 4c 44,46 The dz 2 orbital of cobalt can overlap with the p z orbital of oxygen to form a strong σ-bond, which is attributed to the spatial configuration of the d orbitals. 47,48 52,53 This reveals that the addition of Lewis acid site Al can make the 2-electron ORR process in the cobalt catalytic active site become spontaneous reaction, which is conducive to the progress of ORR. When U = 0.7 V vs RHE, the ΔG *OOH (−0.…”

Sulfur-Vacancy-Rich Pd Metallene Sulfide Nanosheets for the Efficient Electrosynthesis of H2O2

“…Hydrogen peroxide (H 2 O 2 ) is widely used in many fields such as chemical synthesis, biology, medical treatment, and environmental protection. − Up to now, the industrial production of H 2 O 2 still heavily relies on the energy-intensive anthraquinone process, which requires large-scale infrastructure and complicated extraction/purification procedures. − Moreover, direct synthesis from H 2 and O 2 would be accompanied by unnecessary side reactions and high explosion risks. , Therefore, it is of great significance to find green, effective, and safe synthetic pathways for H 2 O 2 production. Two-electron (2e – ) oxygen reduction reaction (ORR) is a promising process for the direct synthesis of H 2 O 2 under ambient conditions. − However, 4e – ORR is thermodynamically more favorable than 2e – ORR, leading to the low selectivity for H 2 O 2 synthesis. − It is necessary to develop an efficient and stable electrocatalyst to promote the implementation of the 2e – ORR pathway via the obstruction of the cleavage of the O–O bond. , …”