In recent decade growing concerns of CO2 emissions from power plants have increased, which led to development of technologies like oxy-fuel combustion process. P91 steel is profoundly used in power plants, but oxy fuel combustion exacerbates corrosion due to recycling of flue gas. This paper studied the kinetics of the corrosion rate on the boiler tubes and furnace and help achieve a corrosion resistant coating over it. Refractory metal diffusion coating is created and tested at high temperature in corrosive atmosphere. This was done by forming Ti and Zr diffusion coating on P91 steel using pack cementation. Coating thickness of 12 and 20 µm were obtained for Ti and Zr respectively. These samples were tested in thermo-gravimetric system by heating at 950˚C for 24 hours in 5% oxygen in Helium gas. Heating in an oxidizing environment lead to exfoliation corrosion on uncoated P91 steel. TGA procedure confirmed less mass change of Ti and Zr coated samples, than that of uncoated P91 steel sample. SEM and depth profiling confirms oxygen penetration is 2.7mm in uncoated P91 steel sample, whereas the Ti and Zr Coated samples oxygen penetration is just 16 and 56 µm respectively.

Energy storage provides sustainability when coupled with renewable but intermittent energy sources such as solar, wave and wind power, and electrochemical supercapacitors represent a new storage technology with high power and energy density. For inclusion in supercapacitors, transition metal oxide and sulfide electrodes such as RuO2, IrO2, TiS2, and MoS2 exhibit rapid faradaic electron–transfer reactions combined with low resistance. The pseudocapacitance of RuO2 is about 720 F/g, and is 100 times greater than double-layer capacitance of activated carbon electrodes. Due to the two-dimensional layered structure of MoS2, it has proven to be an excellent electrode material for electrochemical supercapacitors. Cathodic electrodeposition of MoS2 onto glassy carbon electrodes is obtained from electrolytes containing (NH4)2MoS4 and KCl. Annealing the as-deposited Mo sulfide deposit improves the capacitance by a factor of 40x, with a maximum value of 360 F/g for 50 nm thick MoS2 films. The effects of different annealing conditions were investigated by XRD, AFM and charge storage measurements. The specific capacitance measured by cyclic voltammetry is highest for MoS2 thin films annealed at 500°C for 3h and much lower for films annealed at 700°C for 1 h. Inclusion of copper as a dopant element into electrodeposited MoS2 thin films for reducing iR drop during film charge/discharge is also studied. Thin films of Cu-doped MoS2 are deposited from aqueous electrolytes containing SCN-, which acts as a complexing agent to shift the cathodic Cu deposition potential, which is much more anodic than that of MoS2. Annealed, Cu-doped MoS2 films exhibit enhanced charge storage capability about 5x higher than undoped MoS2 films. Coal combustion is currently the largest single anthropogenic source of CO2 emissions, and due to the growing concerns about climate change, several new technologies have been developed to mitigate the problem, including oxyfuel coal combustion, which makes CO2 sequestration easier. One complication of oxyfuel coal combustion is that corrosion problems can be exacerbated due to flue gas recycling, which is employed to dilute the pure O2 feed and reduce the flame temperature. Refractory metal diffusion coatings of Ti and Zr atop P91 steel were created and tested for their ability to prevent corrosion in an oxidizing atmosphere at elevated temperature. Using pack cementation, diffusion coatings of thickness approximately 12 and 20 µm are obtained for Ti and Zr, respectively. The effects of heating to 950°C for 24 hr in 5% O2 in He are studied in situ by thermogravimetric analyses (TGA), and ex situ by SEM analyses and depth profiling by EDX. For Ti-coated, Zr-coated and uncoated P91 samples, extended heating in an oxidizing environment causes relatively thick oxide growth, but extensive oxygen penetration greater than 2.7 mm below the sample surface, and eventual oxide exfoliation, are observed only for the uncoated P91 sample. For the Ti- and Zr-coated samples, oxygen penetrates approximately 16 and 56 µm, respectively, below the surface. In situ TGA verifies that Ti-and Zr-coated P91 samples undergo far smaller mass changes during corrosion than uncoated samples, reaching close to steady state mass after approximately four hours.