Fang Yuan,Jialin Liang,Shixuan Wang,Jiajia Wang,Bo Chen,Gaofeng Wang,Chunquan Li,Zhiming Sun
Herein, in-situ self-assembly of ZIF-67 derivative on the surface of stilbite and the doping of Ni ions into the Co 3 O 4 lattice were simultaneously achieved through a one-step calcination method. The obtained Ni-doped Co 3 O 4 /stilbite (Ni-Co-AS) exhibited efficient photo-assisted thermal catalytic purification of formaldehyde (HCHO). The results showed that after being regulated by Ni-doped, the Ni-Co-AS composite could achieve efficient photo-assisted thermal catalytic degradation of HCHO driven solely by light. The HCHO removal rate and mineralization rate could reach 93.04 % and 88.60 % within 3 h, respectively. In addition, in order to further improve the photothermal conversion performance of Ni-Co-AS, the composite fiber felt (Ni-Co-AS/F) was prepared from Ni-Co-AS. The conditional experiments show that thermal catalysis is the main mechanism in the photothermal catalytic degradation of formaldehyde by Ni-Co-AS/F. Compared to the pure thermal catalysis (180℃), the presence of light helps to reduce the reaction temperature (120℃) and plays a role in co-catalysis. Ni-Co-AS/F could achieve a higher mineralization rate than that of Ni-Co-AS composite (91.66 %) within 3 h due to the better dispersion and quantum transmission efficiency. In dynamic and long-term degradation experiments, the Ni-Co-AS/F exhibited excellent catalytic performance under the appropriate temperature (35 ± 0.5℃) and humidity (45 ± 3 %) required for the HCHO degradation. This work could effectively provide an efficient and sustainable catalytic material for air pollution control.
In this work, hierarchical flower-like Ni-doped Co 3 O 4 was synthesized via a facile one-step coprecipitation method. In the synthesis process, a series of solvent-dependent experiments were carried out to investigate the effect of ethanol/water ratio (R-E/W) on samples. With the increasing ethanol/water ratio, the doping concentration of Ni 2+ increased and the microstructure evolved from micro-leaves to micro-flowers. Additionally, gas sensors based on prepared materials were fabricated to evaluate their gas sensing properties. The comparative analysis illustrated that the sensor based on 5.3 mol% Ni-doped Co 3 O 4 microflowers (R-E/W = 3/30) presented the highest response (8.34) to 100 ppm n-butanol at low optimum temperature (165 °C), with a response/recovery time of 59/63 s, and it also exhibited excellent anti-humidity properties and long-term stability. The unique hierarchical flower-like microstructure and the optimized parameters (catalytic sites, carrier concentration, ratio of Co 2+ , oxygen component) caused by the doping of Ni were responsible for the improved gas sensing performance. Therefore, this work presented a simple solvent-dependent route to controllably synthesize Ni-doped Co 3 O 4 sensing material, and the excellent gas sensing properties of the sensor based on 5.3 mol% Ni-doped Co 3 O 4 microflowers revealed a great application prospect in detecting n-butanol.
Tiantian Wang,Yue Shi,Jiawei Fei,Jiawei Zhu,Lumin Song,Caixia Li,Tianrong Zhan,Jianping Lai,Lei Wang
Exploring earth-abundant electrocatalysts to replace platinum/iridium for acidic overall water splitting at high current density is an important challenge towards lowering the cost of green hydrogen production . Herein, we developed a new class of three-dimensional interconnected nanofibers (NFs) composed of ultra-small Ni-doped Co 3 O 4 nanoparticles (Ni-Co 3 O 4 NFs). Benefiting from the unique ultra-small Ni-doped Co 3 O 4 composition and three-dimensional interconnected porous structure, 13.4 % Ni-Co 3 O 4 NFs (Ni doping is 13.4 wt%) exhibits remarkable electrocatalytic performance in acidic media. Specially, in strongly acidic environments, high activity and high stability overall water splitting can be achieved at high current density. As evidenced by the fact that a voltage of 500 mA cm −2 can be achieved at only 1.86 V and operational stability can be maintained at 500 mA cm −2 for 100 h.
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