Designing a Built-In Electric Field for Efficient Energy Electrocatalysis

Abstract

To utilize intermittent renewable energy as well as achieve the goals of peak carbon dioxide emissions and carbon neutrality, various electrocatalytic devices have been developed. However, the electrocatalytic reactions, e.g., hydrogen evolution reaction/ oxygen evolution reaction in overall water splitting, polysulfide conversion in lithium− sulfur batteries, formation/decomposition of lithium peroxide in lithium−oxygen batteries, and nitrate reduction reaction to degrade sewage, suffer from sluggish kinetics caused by multielectron transfer processes. Owing to the merits of accelerated charge transport, optimized adsorption/desorption of intermediates, raised conductivity, regulation of the reaction microenvironment, as well as ease to combine with geometric characteristics, the built-in electric field (BIEF) is expected to overcome the above problems. Here, we give a Review about the very recent progress of BIEF for efficient energy electrocatalysis. First, the construction strategies and the characterization methods (qualitative and quantitative analysis) of BIEF are summarized. Then, the up-to-date overviews of BIEF engineering in electrocatalysis, with attention on the electron structure optimization and reaction microenvironment modulation, are analyzed and discussed in detail. In the end, the challenges and perspectives of BIEF engineering are proposed. This Review gives a deep understanding on the design of electrocatalysts with BIEF for nextgeneration energy storage and electrocatalytic devices.

Directional and Ultrafast Charge Transfer in Oxygen‐Vacancy‐Rich ZnO@Single‐Atom Cobalt Core‐Shell Junction for Photo‐Fenton‐Like Reaction

“…[19] Herein, we designed a core-shell heterostructure with n-type ZnO and p-type SACs. The p-n heterojunction creates built-in electric field (BIEF) to form a space-charged (or depletion) region, [20] which spontaneously drives the directional electrons/holes separation and diffuse toward the positively and negatively charged layers. The efficient interfacial charge communication leads to the spatial charge redistribution, which modulates the local electronic structure of the MÀ N x with higher intrinsic activity.…”

Robust Flexible Textile Tribovoltaic Nanogenerator via a 2D 2H‐MoS2/Ta4C3 Dynamic Heterojunction

“…The heterojunction has a typical Schottky contact rectification curve, which indicates that the built-in electric field (E B ) direction formed at the 2H-MoS 2 / Ta 4 C 3 interface is from Ta 4 C 3 to 2H-MoS 2 . [38,39] In addition, previous studies have demonstrated that the induced electric field (E CE ) generated by contact electrification also influences the motion of the heterointerface carriers. [23,26,40] To obtain the direction of the induced electric field, the change of the surface potential of 2H-MoS 2 during the friction process between 2H-MoS 2 and Ta 4 C 3 was tested, as shown in Figure 2D, the surface of 2H-MoS 2 was negatively charged, which indicates that there is contact initiation to induce the direction of the induced electric field from Ta 4 C 3 to 2H-MoS 2 .…”

Field‐assisted electrocatalysts spark sulfur redox kinetics: From fundamentals to applications

“…To smoothly bolster the adsorption-diffusion-conversion process of LiPSs at the interface of the heterostructure, [15,52] the formed built-in EF is usually intertwined with the charge redistribution caused by spontaneous electron transport at the interface, exerting an additional degree of freedom to tune the interfacial electron density, manipulate the charge transfer, and modulate the targeted ion adsorption. [25,[53][54][55] As a representative, when p-type (a semiconductor with holes as majority carriers) and n-type (a semiconductor with electrons as majority carriers) semiconductors have a favorable lattice match and different Fermi energy levels (E F ), the electrons and holes would reversely diffuse and cross the interface until the two levels are aligned, thus generating a built-in EF (Figure 2D). [25,56] In concomitance with favored interfacial chargetransfer kinetics, the anisotropic characteristics are empowered to different components to fully ignite the consecutive adsorption-diffusion-catalysis process of LiPSs on the interface of heterojunctions.…”