In Situ Constructed P–N Junction on Cu₂O Nanocubes through Reticular Chemistry for Simultaneously Boosting CO₂ Reduction Depth and Ameliorating Photocorrosion

Abstract

Photocatalytic CO2 conversion into value‐added chemicals is the one‐stone–two‐birds approach to help meet the carbon neutral goal of near future, and lies on the development of competent photocatalysts that efficiently generate and separate the electron‐hole pairs. Herein, through reticular chemistry a p–n heterojunction is constructed on Cu2O nanocubes by in situ transforming the surface to metal–porphyrin coordination polymer. The resulted Cu2O@Cu‐TCPP core–shell heterostructure, when used for catalyzing CO2 reduction, exhibits not only improved activity, but also enhanced reduction depth. This boosted reducing power is attributed to the improved charge separation efficiency and thus populated charge carriers, as a result of the built‐in electron field of the p–n heterojunction. In addition, the Cu‐TCPP coating serves as a protecting sheath to mitigate the self‐corrosion of Cu2O. Consequently, this study opens a new avenue of photocatalyst design and fabrication for simultaneously promoting multielectron products and ameliorating photocorrosion issues.

Cupric porphyrin frameworks on multi-junction silicon photocathodes to expedite the kinetics of CO2 turnover

“…1a for the schematics) as a result of node–ligand coordination. 30 The intensive Cu–N stretching bands at 1000 cm −1 provide strong evidence for the Cu-coordinated metalloporphyrins in both TCPP(Cu) and SiTCM(Cu), while the N–H fingerprints at ∼980 cm −1 in the spectra of H 2 TCPP and SiTCM are characteristic of freebase porphyrins. 31 In stark contrast, no absorption bands were observed from the ATR-IR spectrum of SiTC and SiT between 800 and 2000 cm −1 owing to their inorganic nature.…”

Emerging Strategies for CO2 Photoreduction to CH4: From Experimental to Data‐Driven Design

“…Photocatalytic heterojunctions are designed by designing the type of semiconductor, [59] the CB/VB potential of the semiconductor, [68] and the Fermi level (E f ) or/and work function (W f ). [44,46] The mechanism of designing the heterojunction to enhance the activity and selectivity of CO 2 photocatalytic reduction to CH 4 is to suppress the recombination of carriers and promote the separation of photoexcited electrons and holes through the built-in electric field.…”

“…The resulting Cu 2 O@Cu-TCPP (TCPP = tetrakis (4-carboxyphenyl) porphyrin) core-shell heterostructure exhibited improved CH 4 production rate and increased selectivity in catalyzing CO 2 reduction, much higher than that of pristine Cu 2 O. [59] In both examples (CuS@ZnIn 2 S 4 and Cu 2 O@Cu-TCPP), the improvement in CH 4 selectivity was attributed to the built-in electric field of the type-II p-n heterojunction, which boosts charge separation efficiency and then populates charge carriers. Notably, in the case of Cu 2 O@Cu-TCPP, the use of Cu-TCPP coating had the added benefit of partially preventing self-corrosion of Cu 2 O, which improved its stability and potential for long-term use during CO 2 photoreduction process.…”

“…[44] Many reported p-n heterojunction photocatalysts follow the charge transfer mode of type-II heterojunction, where the free electrons diffuse from the p-type material into the n-type material region while the holes diffuse from the n-type material into the p-type material. [59] Consequently, a potential difference (i.e., built-in electric field) arising from the uncompensated dopant ions depletes the mobile charges in the zone (i.e., depletion region). Carrier transport across the p-n junction occurs by diffusion and drift processes, which could accelerate the separation of photogenerated electron-hole pairs.…”

Ag Nanoparticles-Induced Metallic Conductivity in Thin Films of 2D Metal–Organic Framework Cu3(HHTP)2

“…This highly increased charge density across the Cu 3 (HHTP) 2 /Ag interface as compared to the CuTCNQ/Ag interface possibly imparts the metallic conduction in the former system. The relevance of AgNPs decoration in other 2D MOFs was investigated by considering an electrically insulating 2D MOF, namely Cu-TCPP (TCPP = tetrakis(4-carboxyphenyl)porphyrin), 47,48 which was subsequently decorated with AgNPs to fabricate AgNPs@Cu-TCPP thin films. The Cu-TCPP system, upon decoration with AgNPs, demonstrated a relatively low enhancement in the electrical conductance value at room temperature, from ∼10 −13 to ∼10 −11 S. Also, variabletemperature I−V analysis of AgNPs@Cu-TCPP thin films revealed a semiconducting behavior (Figure S25).…”