Pulsed electrolysis of carbon dioxide by large-scale solid oxide electrolytic cells for intermittent renewable energy storage

CO_(2) electrolysis with solid oxide electrolytic cells(SOECs)using intermittently available renewable energy has potential applications for carbon neutrality and energy storage.In this study,a pulsed current strategy is used to replicate intermittent energy availability,and the stability and conversion rate of the cyclic operation by a large-scale flat-tube SOEC are studied.One hundred cycles under pulsed current ranging from -100 to -300 mA/cm^(2) with a total operating time of about 800 h were carried out.The results show that after 100 cycles,the cell voltage attenuates by 0.041%/cycle in the high current stage of−300 mA/cm^(2),indicating that the lifetime of the cell can reach up to about 500 cycles.The total CO_(2) conversion rate reached 52%,which is close to the theoretical value of 54.3% at -300 mA/cm^(2),and the calculated efficiency approached 98.2%,assuming heat recycling.This study illustrates the significant advantages of SOEC in efficient electrochemical energy conversion,carbon emission mitigation,and seasonal energy storage.

Dual atomic catalysts from COF-derived carbon for CO_(2)RR by suppressing HER through synergistic effects

The electrochemical carbon dioxide reduction reaction(CO_(2)RR)for highvalue-added products is a promising strategy to tackle excessive CO_(2) emissions.However,the activity of and selectivity for catalysts for CO_(2)RR still need to be improved because of the competing reaction(hydrogen evolution reaction).In this study,for the first time,we have demonstrated dual atomic catalytic sites for CO_(2)RR from a core-shell hybrid of the covalent-organic framework and the metal-organic framework.Due to abundant dual atomic sites(with CoN_(4)O and ZnN_(4) of 2.47 and 11.05 wt.%,respectively)on hollow carbon,the catalyst promoted catalysis of CO_(2)RR,with the highest Faradic efficiency for CO of 92.6%at-0.8 V and a turnover frequency value of 1370.24 h^(-1) at-1.0 V.More importantly,the activity and selectivity of the catalyst were well retained for 30 h.The theoretical calculation further revealed that CoN_(4)O was the main site for CO_(2)RR,and the activity of and selectivity for Zn sites were also improved because of the synergetic roles.

Synthesis of a highly recoverable 3D MnO2/rGO hybrid aerogel for efficient adsorptive separation of pharmaceutical residue

Water contamination by non-steroidal anti-inflammatory drugs,such as acetaminophen,is an emerging ecological concern.In this study,a newthree-dimensionalmanganese dioxideengrafted reduced graphene oxide(3D MnO_(2)/rGO)hybrid aerogel was developed for acetaminophen sequestration.The synthesis involved firstly the self-assembly of GO aerogel,followed by thermal reduction and in-situ MnO_(2) growth by redox-reaction.The aerogel demonstrated interlinked planes with smooth surfaces deposited with MnO_(2) nanospheres and pores of 138.4–235.3μm width.The influences of adsorbent dosage,initial pH,acetaminophen concentration,temperature and contact time were investigated.It was determined that the adsorption of acetaminophen occurred on uniform sorption sites in the aerogel,as suggested by the best fit of data to the Langmuir isotherm,yielding a maximum adsorption capacity of 252.87 mg/g.This highest adsorption performance of the 3D MnO_(2)/rGO aerogel was attained at a dosage of 0.6 g/L,initial pH of 6.2 and temperature of 40℃.The process kinetics were in-line with the pseudo-first-order and pseudo-second-order kinetics at 10 and 20–500 mg/L concentrations,respectively.Thermodynamic assay showed the spontaneity and endothermicity features of the 3D MnO_(2)/rGO-acetaminophen system.The acetaminophen adsorption mechanisms were mainly hydrogen bonding and pore entrapment.Moreover,the as-synthesised aerogel was effectively regenerated using acetone and re-utilised in four adsorption-desorption cycles.Overall,the results highly recommend the implementation of the 3D MnO_(2)/rGO hybrid aerogel for purification of wastewater polluted by acetaminophen residue.