Optimizing interfacial electronic coupling with metal oxide to activate inert polyaniline for superior electrocatalytic hydrogen generation

Abstract

Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts. Herein, experimental and theoretical calculation demonstrate the originally inert N site within polyaniline (PANI) can be activated for hydrogen evolution by proper d-π interfacial electronic coupling with metal oxide. As a result, the assynthesized WO 3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization, exhibits the electrocatalytic production of hydrogen better than other control samples including W 18 O 49 @PANI and most of the reported nobel-metal-free electrocatalysts, with low overpotential of 74 mV at 10 mA·cm −2 and small Tafel slope of 46 mV·dec −1 in 0.5M H 2 SO 4 (comparable to commercial Pt/C). The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO 3 with similar improvements.

Amorphous Ni–Fe–Mo Suboxides Coupled with Ni Network as Porous Nanoplate Array on Nickel Foam: A Highly Efficient and Durable Bifunctional Electrode for Overall Water Splitting

“…The H 2 reduction makes the Mo–O2 peak more intense than that of Mo–O1 peak, and moves the MoO2 bond distance to the negative direction with respect to NiFeMo‐Pre/NF and MoO 3 (Figure S20, Supporting Information). Such changes of EXAFS can be attributed to the formation of oxygen deficiency in the material by H 2 reduction 20a,22. Additionally, the absence of Mo–Mo scattering at distance longer than ≈3.0 Å further manifests the amorphous nature of NiFeMoO x .…”

Visualization of an Accelerated Electrochemical Reaction under an Enhanced Electric Field

“…The face-down configuration could provide a large contact area that stabilizes the microbowls on the ITO slide. According to the literature and our previous derivation [ 26 , 27 ], an enhanced electric field is present at the interface between two mediums with different dielectric properties. Therefore, the electric field line around the heterointerface between the microbowl and ITO surface is more intense than that at the planar surface, which increases the electric strength.…”

In situ observation of heterogeneous charge distribution at the electrode unraveling the mechanism of electric field-enhanced electrochemical activity

“…23 According to the Laplace equation, the electric eld enhancement comes from the difference in the dielectric ability at the interface between two mediums. 4 As a result, the electric eld line around the interface between the Pt and graphite layer should be more intensive than the surrounding planar surface inducing an enhancement of the electric eld strength. electric eld of 18 000 kV cm À1 is obtained at the Pt/graphite interface, as expected ( Fig.…”

“…1 For example, the introduction of defects, adulteration of the electron donor and interfacial electron coupling are known to form "active" regions. [2][3][4] However, the mechanism of these "active" regions in electrochemical reactions is still under investigation. 5 For an electrochemical reaction, the probability of a reaction taking place at the electrode is known to depend on the charge density at the electrode surface and the concentrations of reactants in the diffuse layer.…”