Steering Unit Cell Dipole and Internal Electric Field by Highly Dispersed Er atoms Embedded into NiO for Efficient CO₂ Photoreduction

Abstract

The weak internal electric field over antiferromagnetic materials makes it difficult to facilitate charge migration to the surface, leading to low performance for CO 2 photoreduction. The asymmetry and polarization refinement structure can induce an intensive internal electric field. Herein, n-type NiO is synthesized with highly dispersed erbium atoms doping (Er/NiO 1−x ) via a molten salt method to accelerate charge separation and transfer. The doping of Er atoms can distort the unit cell of NiO to alter the symmetry and enhance the polarization and internal electric field, in favor of efficient separation of charges. In addition, the highly dispersed erbium-doped n-type NiO can largely boost the adsorption and activation of CO 2 , and weaken the energy barrier for CO 2 photoreduction reaction. Benefiting from the unique features, an optimal doping ratio (≈2%) with erbium atoms achieves a remarkable elevation in carrier separation efficiency and excellent CO 2 photoreduction performance with a CO yield of 368 µmol g −1 h −1 in the Ru(byp) 3 2+ /ethanolamine electron-agent generating system, which is 26.3-fold and 3.9-fold relative to traditional NiO and n-type NiO, respectively. The obtained Er/NiO 1−x photocatalyst and the unit cell dipole governing the internal electric field opens a new window for CO 2 photoreduction in antiferromagnetic materials.

Enhanced Photo-Assisted Fenton Degradation of Antibiotics over Iron-Doped Bi-Rich Bismuth Oxybromide Photocatalyst

“…The semi−cycle arc radius in the Nyquist plot of 5%Fe-Bi4O5Br2 is the shortest one, indicative of the quickest carrier transferring rate of this sample being generated. In summary, the doping of Fe atoms into the framework of Bi4O5Br2 resulted in the occurrence of spontaneous polarization and therefore enhancement in the internal electric field, which effectively induced the separation and rapid migration of the photogenerated electron-hole pairs [50]. The recombination kinetics of photogenerated carriers can be comprehensively simulated by the measurement of fluorescence spectra.…”

Enabling Internal Electric Fields to Enhance Energy and Environmental Catalysis

“…In addition, the wet chemical process also leads to structural distortions and loss of symmetry, thus giving rise to internal electric fields. [56,78]…”

“…For example, the incorporation of Er in NiO resulted in significant distortion of NiO unit cells with a well‐aligned internal electric field. [ 56 ] Likewise, the lithiation of TiO 2 distorted the unit cell of TiO 2 to damage the symmetry and increase the polarization, giving rise to an internal electric field. [ 57 ] Although the internal electric fields induced by surface states, piezopotential and Fermi level differences have been discussed and summarized, a systematic and clear rule for the precise regulation of internal electric fields in catalysts is still lacking.…”

“…For example, doping erbium (Er) into n‐type NiO could twist the unit cell of NiO to decrease the symmetry, giving rise to the internal electric field for efficient charge carrier separation and migration. [ 56 ] Moreover, the doping of Er not only reinforced the CB redox potential but also promoted the adsorption and activation of CO 2 . Benefiting from the above advantages, Er‐doped n‐type NiO with a 2% doping ratio can achieve a CO generation rate of 368 µmol g −1 h −1 , which is superior to that of pure NiO and n‐type NiO.…”

Preparation of Heterojunctions Based on Cs3Bi2Br9 Nanocrystals and g-C3N4 Nanosheets for Photocatalytic Hydrogen Evolution

“…In recent times, the field of application of metal halide perovskites (MHPs) has been expanded to photocatalysis, thanks to their excellent optical properties such as high optical absorption coefficient, high carrier mobility and long electron-hole diffusion lengths [ 1 ]. In this vast area of applications, ranging from hydrogen photogeneration and carbon dioxide reduction to H 2 O 2 production to organic dye degradation [ 2 , 3 , 4 , 5 , 6 ]; the need for using lead-free materials is a key aspect of considering the final aims of such uses of MHPs. In general, lead is replaced by elements with similar electronic structure and/or comparable ionic radius, such as Sn 2+ , Ge 2+ , Sb 3+ or Bi 3+ .…”