The combination of water electrolysis and renewable energy to produce hydrogen is a promising way to solve the climate and energy crisis. However, the fluctuating characteristics of renewable energy not only present a significant challenge to the use of water electrolysis electrodes, but also limit the development of the hydrogen production industry. In this study, the effects of three different types of waveforms (square, step, and triangle, which were used to simulate the power input of renewable energy) on the electrochemical catalysis behavior of Ni plate cathodes for HER was investigated. During the test, the HER performance of the Ni cathode increased at first and then slightly decreased. The fluctuating power led to the degradation of the Ni cathode surface, which enhanced the catalysis effect by increasing the catalytic area and the active sites. However, prolonged operation under power fluctuations could have damaged the morphology of the electrode surface and the substances comprising this surface, potentially resulting in a decline in catalytic efficiency. In addition, the electrochemical catalysis behavior of the prepared FeNiMo-LDH@NiMo/SS cathode when subjected to square-wave potential with different fluctuation amplitudes was also extensively studied. A larger amplitude of fluctuating power led to a change in the overpotential and stability of the LDH electrode, which accelerated the degradation of the cathode. This research provides a technological basis for the coupling of water electrolysis and fluctuating renewable energy and thus offers assistance to the development of the “green hydrogen” industry.

Hydrogen sulfide (H₂S) is widely found in oil and natural gas wells and industrial wastewater tanks. Owing to its high toxicity, the monitoring and detection of H₂S in the air is essential. However, recent techniques for the quantitative detection of H₂S gas suffer from limitations such as high cost, complicated operation, and insufficient sensitivity, preventing their practical application in industry. Thus, we have developed a portable test paper for real-time and inexpensive monitoring of H₂S gas by color changes. The test paper had a significantly low H₂S detection limit of 200 ppb, which is considered safe for humans. Moreover, the color of the test paper did not change noticeably when exposed to CO₂, N₂, O₂, and air environments, indicating that the test paper is selective for H₂S gas and can be stored for a long time. In addition, we fitted a color difference linear model between the color difference values (ΔE) and the concentrations of H₂S gas. The establishment of the linear model substantiates that the test paper can provide accurate intensity information when detecting H₂S gas leakage.

To provide carbon steel a long-term corrosion protection effect in NaCl solutions with different pH values, based on poly-acrylamide (PAM) and oleate imidazoline (OIM), a solid corrosion inhibitor with the properties of pH-controlled release was synthesized. SEM, FTIR and TGA results indicated that the OIM inhibitors were successfully loaded into PAM hydrogel with a high OIM encapsulation content (39.64 wt.%). The OIM release behavior from the hydrogel structure has two stages, quick release and sustained release. The pH of solutions could affect the initial release kinetics of OIM inhibitors and the diffusion path in the hydrogel structure. Weight loss measurement of L80 steel in different pH solutions with OIM@PAM proved the inhibitor responsive release mechanism and anticorrosion performance. The inhibition efficiency of OIM@PAM can maintain over 80% after long-term immersion in a harsh corrosive environment (pH 3), which is much higher than the inhibition efficiency of OIM@PAM in a moderate corrosive solution.

In this paper, ethyl cellulose, thermoplastic polyurethane, and mineral oil were used as the main raw materials to synthesize a recyclable thermoplastic gel for anticorrosion coatings by a hot melt method. In addition, the effect of thermoplastic polyurethane on the properties of the coating was discussed. The structure and corrosion protection properties of the coating were characterized and analyzed by a scanning electron microscope, transmission electron microscope, X-ray diffraction, infrared spectroscopy, dynamic mechanical analysis, salt spray test, and electrochemical measurements. The results show that the ethyl cellulose and oil in the coating can form a stable organic-gel structure by hydrogen bonding, and the mineral oil and castor oil are uniformly dispersed in the coating. The surface of the coating does not change after 3000 h of a salt spray test. During the repeated hot melting spraying and immersion in 3.5 wt.% NaCl solution for five times, the electrochemical impedance modulus of the coating was always above 10⁹ Ω⋅cm², the water absorption rate was always less than 1.5 wt.%, and the mechanical properties of the coating did not decrease. This novel coating could be used for the corrosion protection of flange and valve connections in pipeline and bolting connections in different industries. The disassembly and assembly operation of these connection structures during the regular maintenance will destroy the ordinary anticorrosion coating, and the irregular geometric shape of such places also make difficulties for the preparation of ordinary coatings onsite.

The aluminum-basalt fiber composite coating was prepared for the first time with basalt fiber as the spraying material by cold-spraying technology. Hybrid deposition behavior was studied by numerical simulation based on Fluent and ABAQUS. The microstructure of the composite coating was observed on the as-sprayed, cross-sectional, and fracture surfaces by SEM, focusing on the deposited morphology of the reinforcing phase basalt fibers in the coating, the distribution of basalt fibers, and the interaction between basalt fibers and metallic aluminum. The results show that there are four main morphologies of the basalt fiber-reinforced phase, i.e., transverse cracking, brittle fracture, deformation, and bending in the coating. At the same time, there are two modes of contact between aluminum and basalt fibers. Firstly, the thermally softened aluminum envelops the basalt fibers, forming a seamless connection. Secondly, the aluminum that has not undergone the softening effect creates a closed space, with the basalt fibers securely trapped within it. Moreover, the Rockwell hardness test and the friction-wear test were conducted on Al–basalt fiber composite coating, and the results showed that the composite coating has high wear resistance and high hardness.

The self-healing performance of an ethyl-cellulose-based gel coating with different corrosion inhibitors was investigated in this work. Various contents of 11 alkyl imidazoline (IMO-11) were pre-loaded into the gel coating. The EIS results of scratched coatings with inhibitors confirmed the self-healing performance of the coating. As the inhibitor contents increased, the improved self-healing effect was attributed to inhibitor release, while the increased inhibitor content would also affect the film-forming ability and mechanical properties of the composite coating, and lead to the accelerated failure of the coating. Different contents of thiourea and sodium oleate were added to the gel coating with 25% IMO-11. It was hoped that the hybrid inhibitor in the coating would obtain the synergistic effect of different inhibitors during the self-healing progress. The SEM and FT-IR results indicate the hybrid inhibitor was successfully loaded into the gel coating. The EIS and morphology results of scratched coatings confirmed the enhance effect of the synergistic inhibitor on the self-healing performance of the coating. The high content of the hybrid inhibitor could enhance the corrosion protection effect of the intact gel coating. Once the coating is damaged, the fast released inhibitor could extend the corrosion protection time. The synergistic effect difference of thiourea and sodium oleate with IMO-11 did not show much difference in the coating self-healing effect in this work.