Bismuth Nano-Flowers as a Highly Selective Catalyst for Electrochemical Reduction of CO₂to Formate

Abstract

Electrochemical conversion of CO 2 into useful fuels provides tremendous potential for renewable energy storage. This study investigated a predominant nanostructure-dependent catalytic electroreduction of CO 2 into formate on Bi 2 O 3 electrode in 0.5 M KHCO 3 electrolyte. Compared with nano-particle Bi catalyst derived from Bi 2 O 3 nanorods (Bi 2 O 3 -R) electrode, the nano-flowered Bi in situ prepared via reduction of etched Bi 2 O 3 nanorods (Bi 2 O 3 -E) exhibited an enhanced catalytic activity for CO 2 electroreduction to formate. A relatively low overpotential of 530 mV was observed over Bi 2 O 3 -E electrode for formate generation, and the maximum faradaic efficiency (FE) was achieved 99.2% at −1.5 V vs SCE with operating at a current density of 7.5 mA cm −2 , which was superior to that of Bi 2 O 3 -R (FE = 67.9%). Experimental results revealed that the electrochemical active surface area and catalytic activity over reduced Bi 2 O 3 -E electrode were originated from the nano-flowered structure with abundant edge sites. The durability of catalytic activity over Bi 2 O 3 -E lasted at least for 20 h of continuous reaction with negligible decline of FE and current density. This insight may benefit for the further design of surface morphology and structure devoting to improving the catalytic efficiency for CO 2 electroreduction.

Electrochemical Reduction of CO2 to Formate on Easily Prepared Carbon-Supported Bi Nanoparticles

“…Owing to these interesting properties, the employ of Bi-based electrodes towards ECO 2 R to formate (or formic acid) is increasing significantly [56,61,62,63,64,65,66,67,68,69,70,71,72,73]. For instance, Zhang et al studied the electrochemical reduction of CO 2 to formate at room temperature using a high surface area Bi (HAS-Bi) electrocatalyst obtained from the electrochemical reduction of previously prepared BiOCl nanosheets [62].…”

Do Cu Substrates Participate in Bi Electrocatalytic CO2 Reduction?

“…Recently, various metallic materials have been applied as CO 2 electrocatalytic materials, [4] among which Bi‐based materials are widely concerned as a great electrocatalyst for CO 2 converting into formate with high efficiency and selectivity [5] . Many studies focused on Bi morphologies‐efficiency relationships, [6–12] in which Cu was used as the substrates during the preparation of Bi catalysts [13–17] . Some reports believed that the Cu foams provide a highly conductive, and three‐dimensional electrode framework for the deposition of Bi.…”

Tartaric acid regulated the advanced synthesis of bismuth-based materials with tunable performance towards the electrocatalytic production of hydrogen peroxide

“…10,11 Belonging to the semimetal group, the small overlap between the bottom of the conduction band and the top of the valence band provides interesting physicochemical and catalytic properties to bismuth. [12][13][14][15] For instance, bismuth-based composites gained a signification interest as active materials for the photo-/electrocatalytic synthesis of valuable chemicals (production of hydrogen peroxide, 16 ammonia 17 , formate 18,19 , hydrogen 15,20,21 ), the control of the catalytic selectivity, [22][23][24][25] the sensing, 26 and energy conversion [27][28][29][30] applications.…”

“…For the above end-uses, various synthesis methods were developed to prepared different types of micro-and nano-structured materials ranging from metallic Bi to Bi2O3 oxides depending on the designed synthesis protocol. 8,18,19,27,[29][30][31] Since tartaric acid is a triacid and bismuth salts are usually trivalent, the coordination chemistry in an aqueous medium for the production of a variety of morphologies and sizes is of particular interest to study, especially the effect of the alkalinity.…”