TY - JOUR
T1 - Advances in catalytic hydrogen combustion research
T2 - catalysts, mechanism, kinetics, and reactor designs
AU - Kim, Jongho
AU - Yu, Jianglong
AU - Lee, Soonho
AU - Tahmasebi, Arash
AU - Jeon, Chung-Hwan
AU - Lucas, John
N1 - Funding Information:
The higher catalytic activity and stability of bimetallic catalysts compared with monometallic catalysts have been demonstrated in the literature [51, 56?58]. Bimetallic catalysts are prepared by adding materials to a monometallic catalyst. Additives with higher electronegativity result in deficient oxide formation, indicating electrophilic/electrophobic characteristics are crucial factors in controlling catalytic activity [59]. Kaneko et al. [60] investigated Sn- or Zn-modified Pt/Al2O3 to compare their catalytic performances and observed that the Pt?Sn alloy phase formation resulted in enhanced hydrogen conversion. In addition, the Pd?Pt catalyst showed higher resistance to poisoning CHC under lean-burn conditions than the individual Pt and Pd catalysts [49]. Water vapor shows a poisoning effect during the CHC process by blocking and deactivating the active hydrogen-adsorption sites. Lomot et al. [61,62] found that a Pd?Ni catalyst performed better than a Pd/Al2O3 catalyst under low-temperature and lean-burn conditions. Moreover, it has been reported that dealloying bimetallic catalysts by the dissolution of their less reactive parts is another efficient strategy to produce nanoporous, noble-metal catalysts with enhanced catalytic activity [63,64]. An example of such a process was reported by Giarratano et al. [65]. Scanning electron microscopy (SEM) was used to compare a Pt?Cu catalyst on a SiC or polytetrafluoroethylene (PTFE) membrane support before (as-deposited) and after dealloying (Fig. 3). Helium or argon process gases were used in the process. Argon gas led to the formation of columnar gaps on the Pt?Cu thin films, which was not observed when helium gas was employed [65].Equation 8 shows that the total flow rate is proportional to the space velocity, determining the combustion temperature. As the total flow rate increases, while maintaining a constant equivalence ratio, more hydrogen is injected into the combustion system. Veser et al. [126] also reported that the gas outlet temperature increased with the amount of synthetic air; specifically, higher temperatures were observed with 0.75 slpm synthetic air than with 0.5 slpm synthetic air. However, they found that the temperature stabilized at around 1000 ?C, where the equivalence ratio was approximately 0.8. Furthermore, Du Preez et al. [29,30] showed that the combustion temperature of a Pt catalyst supported on a Ti mesh dramatically increased when the total flow rate was increased from 0.2 to 0.3 Nl?min?1 (Fig. 19(a)). Air diffused to be mixture with injected hydrogen gas [29,30]. Meanwhile, as the flow rate increased from 0.4 to 0.6 Nl?min?1, the combustion temperature slightly increased, suggesting that a higher velocity at the inlet nozzle is more likely to ensure the H2 gas passes through the reaction area without reacting.This study was supported by the Australian Research Council Discovery grant (DP210103025) and the National Natural Science Foundation of China (21676132 and 21476100). The PhD scholarship from the University of Newcastle is also greatly appreciated.
Funding Information:
This study was supported by the Australian Research Council Discovery grant ( DP210103025 ) and the National Natural Science Foundation of China ( 21676132 and 21476100 ). The PhD scholarship from the University of Newcastle is also greatly appreciated.
Publisher Copyright:
© 2021 Hydrogen Energy Publications LLC
PY - 2021/11/18
Y1 - 2021/11/18
N2 - Compared with conventional hydrogen-air combustion, catalytic hydrogen combustion (CHC) exhibits higher safety and efficiency and ultra-low NOx emissions. Significant advances in CHC have been achieved in recent years through fundamental research. Therefore, the state-of-the-art CHC technology is comprehensively reviewed herein, including catalyst development, catalytic reactors, and the factors impacting the kinetics of various CHC systems. Furthermore, the progress made in CHC catalyst design over the years is examined, and detailed information regarding their synthesis, structure, and characteristics are presented. The comparison of several types of CHC reactors, including fixed-bed, monolithic, and microchannel reactors, is presented in terms of their operational features and performances. The effects of several operating parameters, including the reaction temperature, hydrogen-to-oxygen stoichiometric ratio, space velocity, residence time, and operating pressure, of the CHC processes are reviewed. The catalytic reaction pathways and the kinetics of the CHC processes are also summarized, advancing the understanding of the underlying chemistry on the catalyst surfaces. This review analyzes the various catalysts, reactor types, operating factors, and underlying mechanisms involved in CHC to better understand the mass transfer, heat transfer, and chemistry during this process. Finally, future research directions are proposed to explore the design of catalytic reactors for CHC.
AB - Compared with conventional hydrogen-air combustion, catalytic hydrogen combustion (CHC) exhibits higher safety and efficiency and ultra-low NOx emissions. Significant advances in CHC have been achieved in recent years through fundamental research. Therefore, the state-of-the-art CHC technology is comprehensively reviewed herein, including catalyst development, catalytic reactors, and the factors impacting the kinetics of various CHC systems. Furthermore, the progress made in CHC catalyst design over the years is examined, and detailed information regarding their synthesis, structure, and characteristics are presented. The comparison of several types of CHC reactors, including fixed-bed, monolithic, and microchannel reactors, is presented in terms of their operational features and performances. The effects of several operating parameters, including the reaction temperature, hydrogen-to-oxygen stoichiometric ratio, space velocity, residence time, and operating pressure, of the CHC processes are reviewed. The catalytic reaction pathways and the kinetics of the CHC processes are also summarized, advancing the understanding of the underlying chemistry on the catalyst surfaces. This review analyzes the various catalysts, reactor types, operating factors, and underlying mechanisms involved in CHC to better understand the mass transfer, heat transfer, and chemistry during this process. Finally, future research directions are proposed to explore the design of catalytic reactors for CHC.
KW - Bimetallic catalyst
KW - Catalytic hydrogen combustion
KW - Heterogeneous catalytic reaction
KW - Kinetics
KW - Perovskite catalyst
UR - http://www.scopus.com/inward/record.url?scp=85118698314&partnerID=8YFLogxK
U2 - 10.1016/j.ijhydene.2021.09.236
DO - 10.1016/j.ijhydene.2021.09.236
M3 - Review Article
AN - SCOPUS:85118698314
SN - 0360-3199
VL - 46
SP - 40073
EP - 40104
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 80
ER -