Research Article
Ir Supported by Mesoporous SiO2 (SBA15) as the Catalyst for Proton Exchange Membrane Water Electrolyzer
Li Jianmin
,
Xu Yunfei,
Kuang Yunhui,
Huang Jianhua,
Xiao Zonghu,
Wang Fahui,
Sun Ling,
Shu Jian,
Li Xiaoping,
Gan Shengquan,
Zou Jun,
John L. Yan,
Liu Bitao*
Issue:
Volume 10, Issue 3, September 2025
Pages:
85-91
Received:
17 July 2025
Accepted:
27 July 2025
Published:
25 August 2025
Abstract: The oxygen evolution reaction (OER) is a critical process in proton exchange membrane (PEM) water electrolysis, but its sluggish kinetics and harsh operational environment e.g., high anodic potentials, oxidative atmosphere, and strong acidic media pose significant challenges to catalyst design. Iridium (Ir) is among the most effective catalysts for OER in acidic conditions; however, its scarcity and high cost necessitate strategies to enhance its efficiency and stability. Reducing the size of Ir nanoparticle to 3-4 nm can significantly enhance OER activity due to an increased surface area and more accessible active sites. In this study, we report the synthesis of a highly active and stable Ir/SBA15 catalyst, in which Ir nanoparticles are uniformly deposited onto mesoporous silica (SBA15). The mesoporous structure of SBA-15 facilitates uniform nanoparticle dispersion, while the incorporation of a conductive nanochain structure enhances electronic conductivity. Transmission electron microscopy (TEM) confirmed the uniform distribution of Ir nanoparticles with an average size of 3-4 nm. Electrochemical tests revealed that Ir/SBA15 exhibits high OER activity, excellent cycling stability, and improved conductivity compared to conventional Ir catalysts. These findings demonstrate that SBA15 supported Ir nanochains offer a promising pathway for efficient and durable OER catalysis in PEM electrolyzers, achieving a balance between catalytic performance, structural integrity, and long-term operational stability.
Abstract: The oxygen evolution reaction (OER) is a critical process in proton exchange membrane (PEM) water electrolysis, but its sluggish kinetics and harsh operational environment e.g., high anodic potentials, oxidative atmosphere, and strong acidic media pose significant challenges to catalyst design. Iridium (Ir) is among the most effective catalysts for...
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Research Article
Geological Formations and the Quagmire of Stream Extinction in Southern Nigeria
Emmanuel Peter Udofia,
Unyime Udoette Saturday*
Issue:
Volume 10, Issue 3, September 2025
Pages:
92-103
Received:
29 June 2025
Accepted:
14 July 2025
Published:
9 December 2025
DOI:
10.11648/j.es.20251003.12
Downloads:
Views:
Abstract: Geology plays a key role in determining the behavior of the ecosystem including its streams network and a better understanding of this concept is the first step toward ecosystem and water sustainability. Hence, this study examines geological formations and the quagmire of stream extinction in Southern Nigeria. Two different geological formations in Southern Nigeria were considered in this study which include the Coastal Plain Sands using Kwa Iboe River in Akwa Ibom State and Basement Complex in some parts of Cross River State. Six matured watersheds were purposively selected from each geological formation (six in Coastal Plain Sands and six in Basement Complex), making a total of twelve (12) watersheds. These cut across Idim Awankwo, Midim, Utu Abak, Anyang, Ibedu and Akpeti watersheds in the Coastal Plain Sands in the Kwa Iboe River and Iwuru, Uyanga, Abonabung, Akor Ako, Okpon and Inyang Iba watersheds in the Basement Complex in Cross River. The result of the summary of the morphometric characteristics shows lower bifurcation ratio in the CPS indicating watersheds in which the geologic structure does not exercise a dominant influence on the drainage pattern while the reverse is the case in BC. In area aspect, the result shows complicated values and high circularity ratio in BC due to the presence of a combination of lithological formations, leading to differential erosion and subsequently to watershed displacement. Statistical analysis using independent t-test analysis shows a p-value of 0.007 which is an indication that there is a significant difference in the morphological parameters of Basement Complex and Coastal Plain Sands as they relate to stream extinction. The summary of the study indicates that streams in the ancient basement complex rocks of Cross River State have restricted area, high values of basin relief and high bifurcation ratio due to inability of streams to erode easily, unlike the weak sedimentary rocks. More so, streams in the CPS recorded less influence from the geological structure of the basins, making the soil have loose particles and highly susceptible to infiltration and highest level of stream extinction. This supports the observable disparity on the basin resilience as one traverse along the river course. Hence, it was recommended that since the CPS is highly prone to stream extinction, desilting the stream channel should be given a priority by stakeholders.
Abstract: Geology plays a key role in determining the behavior of the ecosystem including its streams network and a better understanding of this concept is the first step toward ecosystem and water sustainability. Hence, this study examines geological formations and the quagmire of stream extinction in Southern Nigeria. Two different geological formations in...
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