Construction of Fe₂O₃@CuO Heterojunction Nanotubes for Enhanced Oxygen Evolution Reaction

Abstract

Delicate design and controllable fabrication of efficient oxygen evolution reaction (OER) electrocatalysts based on earth-abundant elements is a highly desired yet challenging task. Herein, Fe2O3@CuO core–shell nanotube heterostructure in situ grown from copper foam (denoted as Fe2O3@CuO NTs/CF) was first synthesized as an efficient OER electrocatalyst. It has been demonstrated that the unique nanotube morphology provided large electrochemical surface area. Moreover, the electron transfer between Fe2O3 and CuO (electronic interaction) within the heterojunction tuned the electronic structure of Cu and Fe sites which not only improved the electron transfer efficiency but also changed the rate-determining step of OER compared with Fe2O3 or CuO, leading to an enhanced OER kinetics (Tafel slope of 41.07 mV dec–1). Benefiting from the structure engineering and electronic modulation, Fe2O3@CuO NTs/CF exhibits an improved activity with 398 mV overpotential at 100 mA cm–2. This work supplies an efficient strategy for fabricating heterostructure catalyst with tubular morphology and modified electronic structure for OER and other electrochemical applications.

Constructed Interfacial Oxygen‐Bridge Chemical Bonding in Core‐Shell Transition Metal Phosphides/Carbon Hybrid Boosting Oxygen Evolution Reaction

“…On the basis of the above data, we speculated that the electron transfer occurred from the CoP shell to the Fe 2 O 3 core in the heterointerface. The electron transfer caused by the heterojunction led to electronic structure modulation to both Fe 2 O 3 @C and CoP exposed surfaces since the carbon layer were thin enough and two phases were in chemical contact (≈10 nm as shown in Figure 1d) according to the previous reports [63] …”

“…The electron transfer caused by the heterojunction led to electronic structure modulation to both Fe 2 O 3 @C and CoP exposed surfaces since the carbon layer were thin enough and two phases were in chemical contact ( � 10 nm as shown in Figure 1d) according to the previous reports. [63] Durability is another important indicator to evaluate the performance of the catalyst. Figure S19 illuminated that the Fe 2 O 3 @C@CoP had a negligible degradation in stability with current densities of approximately 20 mA cm À 2 for 25 h when the applied voltage was set to 1.51 eV, confirming an excellent stability for Fe 2 O 3 @C@CoP in the strongly alkaline electrolyte.…”

Highly Efficient Oxygen Reduction Reaction Activity of N‐Doped Carbon–Cobalt Boride Heterointerfaces

“…[ 45 ] The CoB and N‐doped carbon have constructed heterointerfaces, which lead to fast electron transfer in their electronic structures, thus generating more active sites for ORR. [ 46 ]…”

“…[45] The CoB and N-doped carbon have constructed heterointerfaces, which lead to fast electron transfer in their electronic structures, thus generating more active sites for ORR. [46] The LSV for the catalysts at different rotation rates is illustrated in Figures S9-S11,S12a, Supporting Information. Diffusion current density increases with the rotation speed for all the catalysts, exhibiting their ORR capabilities.…”

Anion Vacancy Engineering in Electrocatalytic Water Splitting

“…The activity of electrocatalysts can be improved as follows: (1) increasing the number of active sites exposed to the electrolyte, (2) enhancing the intrinsic activity of each active site, and (3) improving the electron mobility to utilize active sites fully [12] . Besides, robust stability is a crucial requirement for its large‐scale application in industry [13] . Remarkably, rational anion vacancy engineering on electrocatalyst can efficiently realize the target of excellent performance.…”