Yingjun Qiao,Xianyang Dai,Bing Zhao,Zhiqiang Qian,Zhijian Wu,Zhong Liu
It is highly appealing to use titanium-based adsorbents (like H 2 TiO 3 (HTO)) that have a high capacity and selectivity to directly extract Li + from an aqueous solution. However, HTO still faces the problems of low actual adsorption capacity and dissolution of Ti 4+ , and the application of powder adsorbents is limited by poor fluidity and poor recyclability. In this work, a multi-scale modification strategy was adopted. At the atomic-scale, we prepared Ni-doped HTO-Ni-2 % powder which exhibited higher adsorption capacity (33.27 mg/g) and lower dissolution rate of Ti 4+ (2.2 %) compared to undoped HTO (29.73 mg/g and 2.63 %). Computational studies showed that Ni doping replaced Li in the (Li) layer, resulting in more stable Ni O bonds and enhanced electronic transition ability. At the micro-scale, we have achieved successful granulation of HTO-Ni-2 % using ethylene vinyl alcohol (EVOH) as a binder for the first time. Owing to the increased hydrophilicity by EVOH, the spherical adsorbents exhibited impressive performance, achieving adsorption equilibrium in a short time while maintaining a considerable adsorption capacity (24 h, 10.2 mg/g), and having lower Ti 4+ dissolution. These results have significant implications for developing efficient adsorbents for lithium extraction.
Yang Zhang,Ning Cao,Caihao Wang,Chaocheng Zhao,Yongqiang Wang,Shiyong Zhao,Jinqiang Zhang
Photocatalytic oxygen evolution reaction (OER) is pivotal for sustainable energy systems yet lacks high-performance catalysts capable of strong visible light absorption, robust charge dynamics, fast reaction kinetics, and high oxidation capability. Herein, we report the multiscale optimization of carbon nitride through the construction of porous curled carbon nitride nanosheets (CNA-B30) incorporating boron center/cyano group Lewis acid-base pairs (LABPs). The unique chemical and structural features of CNA-B30 extended the photoabsorption edges of π → π* and n → π* electronic transitions to 470 nm and 715 nm, respectively. Planar distortion and LABPs induced charge redistribution, enhancing the built-in electric field to promote efficient charge dissociation and transport. Moreover, boron atoms elevated the valence band of carbon nitride and served as active oxidation sites, effectively lowering the thermodynamic barrier for water oxidation. As a result, CNA-B30 demonstrated outstanding OER activity, achieving 586.5μmol g −1 h −1 (λ > 420 nm) without co-catalysts. With the addition of a Co co-catalyst, the oxygen evolution rate increased to 2085.5 μmol g −1 h −1 (λ > 420 nm), and an apparent quantum efficiency of 5.8 % at 420 nm, surpassing most state-of-the-art OER photocatalysts. This work offers valuable insights into designing advanced OER photocatalysts for efficient solar fuel production.
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