Water-splitting photoelectrodes consisting of heterojunctions of carbon nitride with a p-type low bandgap double perovskite oxide

Abstract

Quinary and senary non-stoichiometric double perovskites such as Ba 2 Ca 0.66 Nb 1.34−x Fe x O 6−δ (BCNF) have been utilized for gas sensing, solid oxide fuel cells and thermochemical CO 2 reduction. Herein, we examined their potential as narrow bandgap semiconductors for use in solar energy harvesting. A cobalt co-doped BCNF, Ba 2 Ca 0.66 Nb 0.68 Fe 0.33 Co 0.33 O 6−δ (BCNFCo), exhibited an optical absorption edge at ∼800 nm, p-type conduction and a distinct photoresponse up to 640 nm while demonstrating high thermochemical stability. A nanocomposite of BCNFCo and g-C 3 N 4 (CN) was prepared via a facile solvent-assisted exfoliation/blending approach using dichlorobenzene and glycerol at a moderate temperature. The exfoliation of g-C 3 N 4 followed by wrapping on perovskite established an effective heterojunction between the materials for charge separation. The conjugated 2D sheets of CN enabled better charge migration resulting in increased photoelectrochemical performance. A blend composed of 40 wt% perovskites and CN performed optimally, whilst achieving a photocurrent density as high as 1.5 mA cm −2 for sunlight-driven water-splitting with a Faradaic efficiency as high as ∼88%.

Boosting Photocatalytic Activity Using Carbon Nitride Based 2D/2D van der Waals Heterojunctions

“…Recently, Kumar et al. demonstrated a p–n heterojunction of Ba 2 Ca 0.66 Nb 0.68 Fe 0.33 Co 0.33 O 6−δ (BCNFCo) and carbon nitride (BCNFCo/CN) exfoliated in a dichlorobenzene and glycerol mixture (10/1, v/v) that can achieve a photocurrent density as high as 1.5 mA cm –2 under solar simulated light . The low band gap of BCNFCo coupled with intimate contact with exfoliated carbon nitride sheets was attributed for better visible absorption and concomitant capture via carbon nitride.…”

Stability and spectroscopic analysis of CsPbBr3quantum dots modified with 2-n-octyl-1-dodecanol

“…5c and d. 24,36 This effect is attributed to the dielectric limit effect induced by introducing 2-n-octyl-1-dodecanol. In Fig.…”

Predicting Free Energies of Exfoliation and Solvation for Graphitic Carbon Nitrides Using Machine Learning

“…Many efforts have been spent on developing low-cost and large-scale procedures for high-quality g-C 3 N 4 production. Compared with other methods, liquid-phase exfoliation (LPE) has a relatively high yield and low cost. − This method separates the layered g-C 3 N 4 bulk material into monolayered nanosheets in a liquid medium by means of an external force, such as sonication. For the LPE to be successful, the solvent and externally applied force must overcome interlayer interactions such as π–π interaction and hydrogen bonding between neighboring sheets.…”