Single‐atom catalysis for carbon neutrality

Abstract

Currently, more than 86% of global energy consumption is still mainly dependent on traditional fossil fuels, which causes resource scarcity and even emission of high amounts of carbon dioxide (CO 2 ), resulting in a severe "Greenhouse effect." Considering this situation, the concept of "carbon neutrality" has been put forward by 125 countries one after another. To achieve the goals of "carbon neutrality," two main strategies to reduce CO 2 emissions and develop sustainable clean energy can be adopted. Notably, these are crucial for the synthesis of advanced single-atom catalysts (SACs) for energyrelated applications. In this review, we highlight unique SACs for conversion of CO 2 into high-efficiency carbon energy, for example, through photocatalytic, electrocatalytic, and thermal catalytic hydrogenation technologies, to convert CO 2 into hydrocarbon fuels (CO, CH 4 , HCOOH, CH 3 OH, and multicarbon [C 2+ ] products). In addition, we introduce advanced energy conversion technologies and devices to replace traditional polluting fossil fuels, such as photocatalytic and electrocatalytic water splitting to produce hydrogen energy and a high-efficiency oxygen reduction reaction (ORR) for fuel cells. Impressively, several representative examples of SACs (including d-, ds-, p-, and f-blocks) for CO 2 conversion, water splitting to H 2 , and ORR are discussed to describe synthesis methods, characterization, and corresponding catalytic activity. Finally, this review concludes with a description of the challenges and outlooks for future applications of SACs in contributing toward carbon neutrality.carbon neutrality, CO 2 reduction reaction, single-atom catalysts, sustainable clean energy | INTRODUCTIONRapid global industrial revolution with increasing combustion of fossil fuels has led to a substantial increase in greenhouse gas emissions, and the Earth's ecological environment is being irreversibly damaged. In fact, the concentration of carbon dioxide (CO 2 ) has increased drastically in the atmosphere from around 280 ppm (in the early 1800s) to 410 ppm (currently). This has led to a drastic increase in global temperatures and corresponding sea-level rise, as shown in Figure 1. 1 Furthermore, this has also led to disruption in the balance of the carbon cycle. As early as 1960, Syukuro Manabe identified this serious problem and established

Single-atom catalysts for electrochemical applications

“…Up to now, enormous efforts have been made to prepare high-efficiency CO 2 RR electrocatalysts, especially SACs. 1,5,14,[66][67][68][97][98][99][100][101][102] We found that the Ni of the PtNi nanoalloy and the Zn of the ZIF-8-derived Zn 1 on nitrogen-doped carbon experienced metal interchange to produce PtZn nanocrystals and Ni single atoms at high temperature. Due to the synergistic effect of PtZn nanocrystals and Ni 1 -CN, the obtained (PtZn)n/Ni 1 -CN multisite catalysts show lower energy barriers for CO 2 protonation and CO desorption in the CO 2 RR than the reference catalyst, resulting in a greatly enhanced catalytic performance of the CO 2 RR for CO (Fig.…”

“…As thermal energy is being replaced with other types of energy to overcome the activation energy barrier inherent to any chemical transformation, traditional thermal catalysis has been expanded to other types of catalysis such as electrocatalysis, [1][2][3][4][5][6][7][8][9][10][11][12] photocatalysis, 13,14 plasma catalysis, 15,16 and laser catalysis, 17 just to mention a few. This shift, especially to electrocatalysis, is driven by the interest in substituting fossil fuels (which provide heat) with alternative renewable energy sources (like electricity, solar, wind, tidal, etc.).…”

Small‐Scale Big Science: From Nano‐ to Atomically Dispersed Catalytic Materials

“…[7,[52][53][54][55][56][57][58] Recently, the dual/multi-atom site catalysts also have exhibited excellent catalytic activity in energy conversion and catalysis based on synergistic effects between adjacent metal atoms. [59] Compared to SACs, the adjacent metal atoms of dual/multi-atom site catalysts can also collaborate and have a certain synergistic [62] Copyright 2022, The Authors, published by Wenzhou University and John Wiley & Sons Australia, Ltd.…”

“…Timeline of the single-atom catalysts (SACs) with major breakthroughs from 1925 to 2022. Reproduced under the terms of the CC-BY Creative Commons Attribution 4.0 International license (https:// creativecommons.org/licenses/by/4.0) [62]. Copyright 2022, The Authors, published by Wenzhou University and John Wiley & Sons Australia, Ltd.…”

Asymmetric Coordination Environment Engineering of Atomic Catalysts for CO2 Reduction

“…[ 21 , 22 , 23 ]. In these proposed electrochemical reactions, the introduction of catalysts significantly reduces the extra electric energy consumption [ 24 , 25 , 26 , 27 , 28 ]. For traditional bulk and/or nanoparticles (NPs) electrocatalysts, only a few layers of the atoms on the surfaces of the catalysts are involved in the reactions, resulting in a large percentage of the metal atoms being ineffective and wasted.…”