Capturing ion trapping and detrapping dynamics in electrochromic thin films.

Ion trapping has been found to be responsible for the performance degradation in electrochromic oxide thin films, and a detrapping procedure was proved to be effective to rejuvenate the degraded films. Despite of the studies on ion trapping and detrapping, its dynamics remain largely unknown. Moreover, coloration mechanisms of electrochromic oxides are also far from clear, limiting the development of superior devices. Here, we visualize ion trapping and detrapping dynamics in a model electrochromic material, amorphous WO3. Specifically, formation of orthorhombic Li2WO4 during long-term cycling accounts for the origin of shallow traps. Deep traps are multiple-step-determined, composed of mixed W4+-Li2WO4, amorphous Li2WO4 and W4+-Li2O. The non-decomposable W4+-Li2WO4 couple is the origin of the irreversible traps. Furthermore, we demonstrate that, besides the typical small polaron hopping between W5+ ↔ W6+ sites, bipolaron hopping between W4+ ↔ W6+ sites gives rise to optical absorption in the short-wavelength region. Overall, we provide a general picture of electrochromism based on polaron hopping. Ion trapping and detrapping were demonstrated to also prevail in other cathodic electrochromic oxides. This work not only provides the ion trapping and detrapping dynamics of WO3, but also open avenues to study other cathodic electrochromic oxides and develop superior electrochromic devices with great durability.

Epidemiological characteristics of extrapulmonary tuberculosis patients with or without pulmonary tuberculosis.

Our study aimed to investigate the epidemiology of extrapulmonary tuberculosis (EPTB) and analyse the epidemiological characteristics of EPTB patients with or without pulmonary tuberculosis (PTB). EPTB cases admitted in our hospital from January 2015 to December 2020 were included. Uni- and multi-variable logistic regression analysis was carried out to identify risk factors and prognostic factors of concomitant EPTB and PTB or exclusively EPTB. A total of 3488 EPTB patients were reviewed, including 2086 patients with concurrent PTB and EPTB, and 1402 patients with exclusively EPTB. Logistic regression analysis showed that age >60 years (OR = 1.674, 95% CI = 1.438-1.949, P < 0.001) and female (OR = 1.325, 95% CI = 1.155-1.520, P < 0.001) were risk factors of exclusively EPTB, while co-morbidities (OR = 0.676, 95% CI = 0.492-0.929, P = 0.016) and severe symptoms (OR = 0.613, 95% CI = 0.405-0.929, P = 0.021) were risk factors for concurrence of EPTB and PTB. Age >60 years was an independent prognostic factor in EPTB patients with or without PTB (HR = 11.059, 95%CI = 5.097-23.999, P < 0.001; HR = 23.994, 95%CI = 3.093-186.151, P = 0.0020). Female gender was an independent prognostic factor in patients with concurrent PTB and EPTB (HR = 23.994, 95%CI = 3.093-186.151, P = 0.002). Our study disclosed the differential epidemiological characteristics of EPTB patients with or without PTB in China.

Metal Phthalocyanine-Derived Single-Atom Catalysts for Selective CO2 Electroreduction under High Current Densities.

Single-atom catalysts (SACs) with atomically dispersed metal sites in nitrogen-doped carbon matrices (M-N/C) have been identified as promising candidates for the electrocatalytic CO2 reduction reaction (CO2RR). However, recent studies aiming at economic viability have been inhibited by the low faradaic efficiency (FE) and instability under high current density. Herein, we report a series of SACs derived from cyano-substituted metal phthalocyanines (MePc-CN) in ZIFs (denoted as Me-SACs (Pc)). These phthalocyanine molecules enable the efficient construction of SACs, affording higher metal loading and less variation when compared with their counterparts from metal nitrates (denoted as Me-SACs (S)). Thus, Me-SACs (Pc) exhibit higher activities and selectivities than Me-SACs (S) in H-cell measurements. In gas-diffusion electrode (GDE) setups, the unstable Fe-SAC (Pc) shows only a 50% FE of CO (FEco) at -100 mA cm-2. In contrast, Ni-SAC (Pc) exhibits a higher FEco of >96% at current densities from -10 to -200 mA cm-2 and can stably operate for over 16 h at -200 mA cm-2. The performances of Ni-SAC (Pc) are comparable to those of precious metal catalysts and the best SACs reported so far, representing a promising candidate for practical electrolyzer devices for CO2RR.