Toward an Understanding of the Enhanced CO₂ Electroreduction in NaCl Electrolyte over CoPc Molecule‐Implanted Graphitic Carbon Nitride Catalyst

Abstract

Direct CO2 electrolysis in seawater enables the simultaneous conversion of CO2 into CO and the chlorine ions into Cl2, further meeting downstream industry needs such as phosgene synthesis and also facilitating the net consumption of CO2. As a result, the direct implementation of CO2 electrolysis in seawater is urgently required. Herein, a CoPc molecule‐implanted graphitic carbon nitride nanosheets (CoPc/g‐C3N4) electrocatalyst is prepared via a simple mechanochemistry method. The CoPc/g‐C3N4 with a negatively charged surface and preferential adsorption capability for Na+ can achieve appreciable faradaic efficiency (FE, 89.5%) toward CO with a current density of 16.0 mA cm−2 in natural seawater and also realize long‐term operation for 25 h in simulated seawater. Process monitoring further reveals that the chlorine ions in NaCl electrolyte can modulate the reaction microenvironment around the anode, which in turn has positive effects on the CO2RR in cathode. The CO2RR overall splitting in the simulated seawater exhibits a maximum FE of 98.1% towards CO at cell voltage of 3 V. This work describes the development of a carbon‐coupled CoPc molecular catalyst that can drive the CO2 electrolysis in simulated seawater and provides a promising and energy‐saving coupled reaction system for direct coproduction of CO and Cl2.

Electronic Structure Optimization of PdZn-Graphitic Carbon Nitride Nanocomposites as Electrocatalysts for Selective CO2 to CO Conversion

“… 1 Hence, a more negative zeta potential for PdZnGCN corroborates its better catalytic performance, enhanced kinetics, and, consequently, higher TOF and FE. 1 …”

“…1 Hence, a more negative zeta potential for PdZnGCN corroborates its better catalytic performance, enhanced kinetics, and, consequently, higher TOF and FE. 1 Adsorption tests were carried out using PdZnGCN, PdZn, and GCN catalysts. The result indicates that the amount of CO 2 adsorbed followed the order with PdZnGCN (4.33 cm 3 / g) > GCN (3.32 cm 3 /g) > PdZn (2.20 cm 3 /g), whereas the amount of CO desorbed was PdZnGCN (1.18 cm 3 /g) > PdZn (1.04 cm 3 /g) > GCN (0.76 cm 3 /g), as summarized in Table S6.…”

“…The increase in fossil fuel consumption has led to a growing urgency to reduce carbon dioxide emissions and develop sustainable energy technologies. 1 , 2 Recently, research to find an alternative energy source by converting CO 2 into carbon-neutral fuels has been intensified. Electrochemical reduction is attractive as it can employ green electrolytes, utilize surplus electricity from renewable energy resources, and adjust device performance through optimization of catalysts.…”

“…The increase in fossil fuel consumption has led to a growing urgency to reduce carbon dioxide emissions and develop sustainable energy technologies. , Recently, research to find an alternative energy source by converting CO 2 into carbon-neutral fuels has been intensified. Electrochemical reduction is attractive as it can employ green electrolytes, utilize surplus electricity from renewable energy resources, and adjust device performance through optimization of catalysts. , However, the electrochemical CO 2 reduction reaction (ECO 2 RR) still suffers from high overpotential, low selectivity, and poor long-term stability due to the high thermodynamic stability of CO 2 and competing hydrogen evolution reactions .…”

Strategies to activate inert nitrogen molecules for efficient ammonia electrosynthesis: current status, challenges, and perspectives

“…236 More meaningfully, coupling the electrocatalytic NRR with the chlorine evolution reaction (2Cl À -Cl 2 + 2e À ) at the anode in a seawater electrolyte also provides the possibility of synthesizing value-added products or feedstocks towards downstream industrial processes. 237 In another case, the pH value of the aqueous electrolyte, which can influence the form of proton donors (H 2 O or H 3 O + ) involved in the NRR process, also needs to be considered. 17,238 Nonaqueous electrolytes, which include organic electrolytes (with/ without water) and ionic liquids, can usually retard the HER activity, which is favorable for acquiring a high NRR selectivity.…”