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Carbon neutrality is a goal the world is striving to achieve in the context of global warming. Carbon capture and storage (CCS) has received extensive attention as an effective method to reduce carbon dioxide (CO2) in the atmosphere. What follows is the migration pathway and leakage monitoring after CO2 injection. Interferometric synthetic aperture radar (InSAR) technology, with its advantages of extensive coverage in surface deformation monitoring and all-weather traceability of the injection processes, has become one of the promising technologies frequently adopted in worldwide CCS projects. However, there is no mature evaluation system to determine whether InSAR technology is suitable for each CO2 sequestration area. In this study, a new evaluation model is proposed based on the eight factors that are selected from the principle of the InSAR technique and the unique characteristics of the CO2 sequestration area. According to the proposed model, the feasibility of InSAR monitoring is evaluated for the existing typical sequestration areas in the world. Finally, the challenges and prospects of InSAR in the CCS project are discussed. [ABSTRACT FROM AUTHOR]

Carbon Capture, Utilization and Storage, also referred to as Carbon Capture, Utilization and Sequestration (CCUS), is one of the novel climate mitigation technologies by which CO2 emissions are captured from sources, such as fossil power generation and industrial processes, and further either reused or stored with more attention being paid on the utilization of captured CO2. In the whole CCUS process, the dominant migration pathway of CO2 after being injected underground becomes very important information to judge the possible storage status as well as one of the essential references for evaluating possible environmental affects. Interferometric Synthetic Aperture Radar (InSAR) technology, with its advantages of extensive coverage in surface deformation monitoring and all-weather traceability of the injection processes, has become one of the promising technologies frequently adopted in worldwide CCUS projects. In this study, taking the CCUS sequestration area in Shizhuang Town, Shanxi Province, China, as an example, unmanned aerial vehicle (UAV) photography measurement technology with a 3D surface model at a resolution of 5.3 cm was applied to extract the high-resolution digital elevation model (DEM) of the study site in coordination with InSAR technology to more clearly display the results of surface deformation monitoring of the CO2 injection area. A 2 km surface heaving dynamic processes before and after injection from June 2020 to July 2021 was obtained, and a CO2 migration pathway northeastward was observed, which was rather consistent with the monitoring results by logging and micro-seismic studies. Additionally, an integrated monitoring scheme, which will be the trend of monitoring in the future, is proposed in the discussion. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO 2 reduction (CO 2 ER) to produce formic acid (HCOOH) would be an attractive means for carbon neutralization. In order to realize efficient CO 2 ER and economical conversion of CO 2 , the applying of metal active sites on surface of semiconductor has emerged as a promising strategy. Herein, we report the preparation of alkaline modified TiO 2 nanowires (NWs) as the substrate for Au photodeposition. The as-fabricated Au/TiO 2 NWs exhibits high activity and selectivity towards HCOOH production compared with traditional catalysts. The key factors including deposition time, solution, and etc. And their effects on CO 2 ER performance have been systematically investigated. At −0.8 V vs RHE, the Faraday efficiency of the HCOOH can reach to 86.49 %, while the current density is 15.94 mA cm−2. In addition, Au/TiO 2 NWs also exhibited good stability after 18 h electrocatalytic CO 2 RR under the voltage of −0.8 V vs RHE. Electrochemical tests indicated that Au/TiO 2 NWs process favorable intrinsic electrochemical properties, high ESCA and accelerating charge transfer process make Au/TiO 2 NWs obtain abundant active sites and kinetically favorable. This work provides a convenient fabrication strategy of Au/TiO 2 based catalyst, which can guide the design and modification of gold for CO 2 ER into formic acid. [Display omitted] • A low-cost fabrication strategy of self-supported Au/TiO 2 from alkaline modified TiO 2 nanowires and photodeposited Au. • The photodeposition conditions were optimized to tune the CO 2 reduction active sites on Au/TiO 2. • Metal-support interaction between Au and TiO 2 modulate the electronic structure and promote CO 2 reduction. • Prepared Au/TiO 2 NWs efficient catalytic CO 2 conversion to formic acid (FE HCOOH = 86.49 %, @−0.8 V vs. RHE). [ABSTRACT FROM AUTHOR]

The development of efficient, recyclable and low‐cost heterogeneous catalysts for conversion of carbon dioxide (CO2) into epoxides is highly desired, yet remain a challenge. Herein, we have prepared three two‐dimensional (2D) copper(I) cyclic trinuclear units (Cu(I)‐CTUs) based covalent metal–organic frameworks (CMOFs), namely JNM‐13, JNM‐14, and JNM‐15, via a one‐pot reaction by combination of coordination and dynamic covalent chemistry. Among them, JNM‐15 contained the highest density of copper catalytic sites, and exhibited the highest capacity for adsorption of CO2. More interestingly, JNM‐15 delivered the highest catalytic activity for cycloaddition of CO2 to epoxides with good yields (up to 99 %), good substrate compatibility (11 examples) and reusability (four catalytic cycles) under mild condition. [ABSTRACT FROM AUTHOR]

• Direct synthesis of N-doped porous carbons (PCs) using PAN and NaNH 2 simplifies production. • Optimized sample PN-3 shows a high specific surface area (SSA) of 2490 m2/g. • PN-3 exhibits significant CO 2 adsorption: 7.15 mmol/g at 273 K, 4.56 mmol/g at 298 K. • Outstanding CO 2 /N 2 selectivity (∼102) surpasses many other N-doped carbons. • Modest heat of adsorption (39.10 kJ/mol) allows energy-efficient regeneration. N-doped porous carbons (PCs) are extensively researched for CO 2 capture and separation under flue gas conditions, but their complex and expensive preparation methods hinder widespread industrial use. Herein, we present a direct approach for synthesizing N-doped PCs by utilizing polyacrylonitrile (PAN) and NaNH 2 as precursors, without the need for any solvents. The utilization of NaNH 2 as both a porogen and nitrogen supply during carbonization is primarily responsible for the formation of the well-developed pore structure and high specific surface area of N-doped PCs. The optimized sample "PN-3" demonstrated excellent textural features with an excellent specific surface area (SSA) of 2490 m2/g, a pore volume of 2.0559 cm3/g, a well-defined pore size distribution (PSD), and abundant micropores (<1 nm). In addition, PN-3 has the highest pyrrolic nitrogen content (∼40.1 at.%), resulting in a significant capacity for CO 2 adsorption (7.15 mmol/g at 273 K/1bar, 4.56 mmol/g at 298 K/1 bar, 26.2 mmol/g at 298 K/ 40 bar). Furthermore, it exhibits an outstanding CO 2 /N 2 selectivity (∼102) based on the ideal adsorbed solution theory (IAST) at 273 K, surpassing the performance of most of previously reported biomass and polymer-derived N-doped carbons in terms of CO 2 adsorption and separation. In addition, the adsorption process is characterized by a modest heat of adsorption (39.10 kJ/mol) and a steady cyclic pattern of CO 2 adsorption–desorption under flue gas settings (15 % CO 2 and 85 % N 2). This indicates that the adsorption is mostly governed by physisorption, which allows for an energy-efficient regeneration process. In summary, this study showcases the successful production of highly PCs that can effectively adsorb CO 2 , enlightening the way toward establishment of a cost-effective and facile synthetic protocol for achieving CO 2 capture/separation at the commercial scale. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped porous carbon (NPC) was fabricated via a novel one-step solvent-free melt polycondensation. • Potassium citrate served as both a template and an activator to create abundant microporous structure. • NPC delivered an excellent CO 2 adsorption capability at 4.16 mmol·g−1 at 100 kPa. • NPC exhibited a fast adsorption kinetics and an outstanding uninterrupted recyclability. • The CO 2 adsorption mechanism on NPC was ascribed to multi-layer adsorption by the micropore filling. Heteroatomic doped porous carbon (HPCs) is a promising advanced material, showing great application potential in greenhouse gas capture. Here, in-situ N-doped porous carbon (NPC) was developed via a novel and readily scalable strategy − one-step solvent-free melt polycondensation assisted by organic potassium salts, followed by pyrolysis and activation. As both a template and an activator, the added C 6 H 5 K 3 O 7 played an important role to create abundant microporous structure. The as-fabricated NPC-650–0.5 showed a rich N content (6.11 at.%), abundant narrow micro-porosity (0.3437 cm3·g−1), and a high surface area (1209.37 m2·g−1) and delivered an excellent CO 2 static adsorption capacity (4.16 mmol·g−1 and 8.40 mmol·g−1 at 100 and 500 kPa), a fast adsorption kinetics (circa 98% of balance capacity in 12 min), moderate heat of adsorption (25 to 30 kJ/mol), high selectivity of CO 2 /N 2 , and outstanding uninterrupted recyclability. Both the narrow micropore volume and N-doping sites had strong effects on the CO 2 adsorption capacity, indicating a physical and chemical adsorption process with the mechanism being multi-layer adsorption by the micropore filling. This work highlights the great potential of the NPC-650–0.5 for capturing CO 2 and offers new insights into a green activator and a simple and easy-to-scale method for preparing HPCs. [ABSTRACT FROM AUTHOR]

Heteroatom-doped porous carbon materials (HPCMs) have attracted great attention due to their excellent physical and chemical properties and the enhanced performance of multiple heteroatom co-doping. Herein, N, P-co-doped porous carbon materials (NPPCs) are developed via a novel synthesis of the phytic acid-induced self-assembled chitosan aerogel followed by pyrolysis and activation. Phytic acid serves as a P source, acid regulator and structure-directing agent for improved activation efficiency to create more pores. A little of NaNO 3 is used both as a template and activator simultaneously. The porosity and N content of such NPPCs are controlled by rationally tuning the pyrolysis temperature and the mount of NaNO 3. The NPPC-0.75-600 delivers a good CO 2 adsorption capability of 3.02 and 5.31 mmol g−1 at 100 and 500 kPa, respectively, and has an excellent stability with almost no adsorption capacity decay even after successive 20 cycles. For supercapacitors (SCs), the NPPC-0.75-700 also displays a high capacitance of 231.2 F g−1 at 1 A g−1 and an outstanding stability at circa 96.7% initial capacity after 10000 cycles. These results highlight the great potential of such NPPCs in CO 2 capture and SCs, and the novel synthetical route offers new insights for the readily scalable production of HPCMs. [Display omitted] • Phytic acid induced chitosan gel and served as a P source and activation agent. • N,P-co-doped porous carbon delivered a CO 2 capture ability of 5.31 mmol g−1 at 298 K. • N,P-co-doped porous carbon exhibited specific capacitance at 231.2 F g−1 at 1 A g−1. • CO 2 capture and supercapacitor performances were substantially improved by P doping. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quantitatively CO 2 -responsive, ratiometric fluorescence sensor synergizing TPE and Au NCs was firstly reported. • Water-soluble TPE-ssHPA-Ac@Au NCs composites without participation of any free organic compounds were constructed. • The ratiometric sensor showed reversible photoluminescence response to CO 2 /N 2 cycling. • The ratiometric sensor showed reversible emission color change to CO 2 /N 2 cycling. Nowadays, developing effective CO 2 detecting methodologies is of great significance. Herein, a hybrid ratiometric fluorescence sensor by decorating tetraphenylethene (TPE) and gold nanoclusters (Au NCs) into disulfide functionalized hyperbranched poly(amido amine) skeleton was designed for efficient and accurate ratiometric detection of dissolved CO 2 in the range of 3.8 × 10−4 – 1.9 × 10-2 mol·L-1 with a detection limit of 7.8 μ M. The emission ratio and color were reversible through switching the CO 2 /N 2 stimuli. Finally, this fluorescent probe was proven to be effective for determining the CO 2 concentration in real samples. This is the first report of water-soluble, quantitatively CO 2 -responsive, ratiometric fluorescence sensor synergizing TPE and Au NCs in the amino-rich hyperbranched skeleton without participation of any free organic compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • N,S-containing polycondensates were synthesized by one-pot polycondensation reaction. • The N,S codoped porous carbon was fabricated by pyrolysis and activation of N,S-containing polycondensates. • The N,S-codoped porous carbon exhibited a high CO 2 capture ability of 5.56 mmol/g at 298.15 K. • The N,S-codoped porous carbon showed an ultrahigh specific capacitance at 224.3F·g−1 at 1 A·g−1. • The all solid-state symmetrical NSPC-1-650-based supercapacitors delivered a high energy density and power density. Nitrogen-sulfur codoped porous carbon (NSPC) is a promising advanced material, showing great application potential in greenhouse gas capture and energy storage. Here, a novel NSPC with controllable porous structure was fabricated via pyrolysis and activation of N, -containing polycondensates, which were synthesized by one-pot polycondensation reaction of triglycidyl isocyanurate, glucose and thiourea. The obtained sample NSPC-1-650 showed cross-linked spherical morphology with uniform pore size (2.61 nm), large specific surface areas (1927.46 m2·g−1), and the doping of nitrogen (4 wt%) and sulfur (2 wt%), which leaded to a good CO 2 adsorption capability (5.56 mmol·g−1 at 298.15 K, 5 bar) and excellent stability. Additionally, when used as a supercapacitor, the NSPC-1-650 sample showed an ultrahigh specific capacitance (224.3F·g−1 at 1 A·g−1 in 6 M KOH electrolyte), an excellent rate capability, and good stability (retained > 85% capacity after 5000 cycles). Notably, the all solid-state symmetrical NSPC-1-650-based supercapacitors delivered a high energy density (the maximal value = 7.8 Wh·Kg−1) and power density (the maximal value = 4500 W·Kg−1). These results suggest that NSPC-1-650 be a competitive candidate as a CO 2 adsorbent and supercapacitor. [ABSTRACT FROM AUTHOR]

The functionalization of silver surface with cobalt (II)-complexes allows to build functional electrodes for efficient electrolysis CO 2 reduction to CO. The interplays between surface ligands and the multiple constituents of the electrocatalytic interface are critical to improve catalytic performance during CO 2 electrolysis, which would provide new opportunities for construction and design of high-efficient catalysts toward CO 2 reduction. [Display omitted] • Metal-molecule interaction constructed by cobalt complexes improved the electrocatalytic CO 2 reduction performance of bulk silver. • Interaction between metal–molecule catalysts adjusts electrocatalytic performance by tuning electronic structure, inhabiting strong hydrogen evolution, and enhancing silver-based catalyst activity for CO 2 RR. • Co(bpy) 3 2+ molecules increasing the number of electrochemically working sites, it is possible to increase the electrocatalytic activity. • Co(bpy) 3 2+ molecules adsorbed on the surface of Ag forming a metal–molecule catalyst, increasing local concentration of CO 2 and stabilizing the intermediate, performance is improved in metallic electrocatalysts. Electrochemical conversion of CO 2 into CO, powered by renewable electricity, offers one means to address the need for the storage of intermittent renewable energy. However, it is challenging because the competing HER is hard to avoid, which significantly compromises the selectivity to CO and reduces the efficiency of CO 2 RR devices. This study reports a cooperative catalyst design of metal–molecule catalyst interfaces with the goal of high local concentration of CO 2 and stabilizing the intermediate, which improves the electrosynthesis of CO. The strategy is implemented by functionalizing the silver surface with cobalt (II)-complexes to promote the selective electrolysis of CO 2 to CO. We report a CO 2 -to-CO Faradaic efficiency of 98.5 % and a partial current density of 16.52 mA cm−2 at − 1.1 V vs. RHE. Mechanism studies reveal that the catalytic performance of the Ag/Co(bpy) 3 2+ correlates with the metal–molecule interaction, which provide new opportunities for construction and design of high-efficient catalysts toward CO 2 reduction. [ABSTRACT FROM AUTHOR]

Traditional wet and dry Chromite Ore Processing Residue (COPR) detoxification methods consume acid for pH adjustment and produce greenhouse gasses (CO 2), yielding potential secondary pollution. It is imperative to develop an environmentally-friendly, efficient, and effective method for COPR treatment. This study reported the one-step natural pyrite-assisted mechanochemical detoxification of Cr(VI) in COPR. Under optimal conditions (i.e., the pyrite/COPR mass ratio of 5% and mechanochemical treatment at 600 rev./min for 2.5 h), Cr(VI) in COPR was efficiently reduced and immobilized, and the leaching concentration of total Cr met the regulatory limit of 5 mg/L. The X-ray absorption near-edge structure (XANES) analysis further verified that the Cr(VI) in treated COPR was 100% reduced to Cr(III). Potential mechanism could be that the enclosed non-exchangeable Cr(VI) in the chromite matrix was exposed to the COPR particle surface under the mechanical action; then, the redox reaction between pyrite and Cr(VI) were induced and enhanced through accumulated crystal defects and generated new surfaces with dangling bonds under mechanical forces. Life cycle assessment (LCA) results highlight that the high energy input is the major contributor eliciting environmental impacts for this current technology. More efficient and cleaner energy supplies should be sought alternatively to overcome the overall sustainability. [Display omitted] • Chromite liberation and destruction exposed Cr(VI) for reduction by pyrite. • XANES analysis verified that the Cr(VI) was 100% reduced to Cr(III). • The mechanochemical treatment produces low wastewater and greenhouse gas emissions. [ABSTRACT FROM AUTHOR]