Unveiling hydrocerussite as an electrochemically stable active phase for efficient carbon dioxide electroreduction to formate

Abstract

For most metal-containing CO 2 reduction reaction (CO 2 RR) electrocatalysts, the unavoidable self-reduction to zero-valence metal will promote hydrogen evolution, hence lowering the CO 2 RR selectivity. Thus it is challenging to design a stable phase with resistance to electrochemical self-reduction as well as high CO 2 RR activity. Herein, we report a scenario to develop hydrocerussite as a stable and active electrocatalyst via in situ conversion of a complex precursor, tannin-lead(II) (TA-Pb) complex. A comprehensive characterization reveals the in situ transformation of TA-Pb to cerussite (PbCO 3), and sequentially to hydrocerussite (Pb 3 (CO 3) 2 (OH) 2), which finally serves as a stable and active phase under CO 2 RR condition. Both experiments and theoretical calculations confirm the high activity and selectivity over hydrocerussite. This work not only offers a new approach of enhancing the selectivity in CO 2 RR by suppressing the self-reduction of electrode materials, but also provides a strategy for studying the reaction mechanism and active phases of electrocatalysts.

Toward computational design of chemical reactions with reaction phase diagram

“…The applications of reaction phase diagram have shown a great success understanding experimental results, where the predicted activity variations have been verified by several experiments. 22,[49][50][51][53][54][55]63 The volcano plot at the thermodynamic level indicates it is usually a reasonable prediction for electrocatalysis. 26 However, some thermochemical processes do occur in electrocatalysis, for instance, C-N bond synthesis and C-C coupling.…”

“…20 Note that, the scaling relations have also been found crossing different kinds of materials. [48][49][50] The correlated energies ensure a great foundation for reaction phase diagram analysis. In the following, we will review several applications of using reaction phase diagram to understand the experiments of catalytic reactions with a single reaction pathway, double reaction pathways, and more complex reaction pathways.…”

“…CO 2 electrocatalytic reduction producing formate is another valuable way of committing to carbon recycling. 49,55 Hydrocerussite was studied and showed a high selectivity of producing formate in experiments. A theoretical study was conducted using reaction phase diagram, based on the scaling relations between adsorption energies of COOH*, CO*, and H* with respect to the descriptor (adsorption energies of HCOO*).…”

“…A theoretical study was conducted using reaction phase diagram, based on the scaling relations between adsorption energies of COOH*, CO*, and H* with respect to the descriptor (adsorption energies of HCOO*). 49 Note that, all the scaling relations were built based on different active sites over the perfect and defect hydrocerussite surfaces. Two competitive pathways (CO 2 protonation to COOH* or HCOO*) can be obtained from the complete pathway construction, resulting in a double-peak volcano curve (Figure 7 (a), red lines).…”

Optimization Strategies for Selective CO2 Electroreduction to Fuels

“…Although hydrocarbons and alcohols are thermodynamically favored, CO and HCOOH/HCOO − are kinetically preferred because they require fewer electron transfers to complete the reaction (2e − products) [11]. As a result, CO and formic acid, as the most common CO 2 RR products, usually show high selectivity using either metal or metal-free cathodes [15][16][17][18]. Meanwhile, products involving > 2e − transfer are prone to desorbing from the electrode surface before deep reductions occur, leading to low selectivity.…”