Progress in electrocatalytic nitrate reduction for green energy:Catalyst engineering,mechanisms,and techno-economic feasibility

Ammonia(NH_(3))is an irreplaceable chemical that has been widely demanded to keep the sustainable development of modern society.However,its industrial production consumes a huge amount of energy and releases extraordinary greenhouse gases(GHGs),leading to various environmental issues.Achieving the green production of ammonia is a great challenge,which has been extensively pursued in the last decade.In this review,the most promising strategy,electrochemical nitrate reduction reaction(e-NO_(3)RR),is comprehensively investigated to give a complete understanding of its development and mechanism and provide guidance for future directions.However,owing to the complex reactions and limited selectivity,a comprehensive understanding of the mechanisms is crucial to further development and commercialization.Moreover,NO_(3)^(-)RR is a promising strategy for simultaneous water treatment and NH_(3)production.A detailed overview of the recent progress in NO_(3)^(-)RR for NH_(3)production with nontransition and transition metal based electrocatalysts is summarized.In addition,critical advanced techniques,future challenges,and prospects are discussed to guide future research on transition metal-based catalysts for commercial NH_(3)synthesis by NO_(3)^(-)reduction.

Atomic Dispersed Hetero‑Pairs for Enhanced Electrocatalytic CO_(2)Reduction

Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale.

Integrated device for multiscale series vibration reduction and energy harvesting

A multi-degree-of-freedom device is proposed,which can achieve efficient vibration reduction as the main objective and energy harvesting as the secondary purpose.The device comprises a multiscale nonlinear vibration absorber(NVA)and piezoelectric components.Energy conversion and energy measurement methods are used to evaluate the device performance from multiple perspectives.Research has shown that this device can efficiently transfer transient energy from the main structure and convert a portion of transient energy into electrical energy.Main resonance and higher-order resonance are the main reasons for efficient energy transfer.The device can maintain high vibration reduction performance even when the excitation amplitude changes over a large range.Compared with the single structures with and without precompression,the multiscale NVA-piezoelectric device offers significant vibration reduction advantages.In addition,there are significant differences in the parameter settings of the two substructures for vibration reduction and energy harvesting.

Novel Brick Technology for Carbon Reduction Footprint in Steel Shop Linings

Clean steel encompasses a multitude of concepts that are based on fulfilling customer requirements and can be produced in many ways depending on the existing equipment and detailed customer demands.A common feature of all clean steel production is tight process control along with continuous monitoring.To meet an increasing demand for cold-rolled(CR)steel sheets of improved mechanical properties,and to cope with the change of the annealing process from a batch-type to a continuous process,it is necessary to establish a technique for making ultralow carbon(ULC)steel with a C-concentration lower than 20 ppm for the steelmaking process associated with a major challenge to guarantee the competitiveness with observance of environmental requirements.Steel ladle lining plays an important role on the energy consumption during the production and the refractory lining design contributes to minimize thermal bath loss,carbon pick up and shell temperature.A new generation of unfired zero carbon refractories was developed with two specific approaches:(1)replacement of firing bricks reducing CO_(2) footprint and(2)replacement of carbon containing with performance increasing.Bricks can be used in working and safety linings with a unique microstructure with better heat scattering and similar thermomechanical properties.This work presents customers’performance compared to traditional products highlighting energy savings.

Efficient Energy and Delay Reduction Model for Wireless Sensor Networks

In every network,delay and energy are crucial for communication and network life.In wireless sensor networks,many tiny nodes create networks with high energy consumption and compute routes for better communication.Wireless Sensor Networks(WSN)is a very complex scenario to compute minimal delay with data aggregation and energy efficiency.In this research,we compute minimal delay and energy efficiency for improving the quality of service of any WSN.The proposed work is based on energy and distance parameters as taken dependent variables with data aggregation.Data aggregation performs on different models,namely Hybrid-Low Energy Adaptive Clustering Hierarchy(H-LEACH),Low Energy Adaptive Clustering Hierarchy(LEACH),and Multi-Aggregator-based Multi-Cast(MAMC).The main contribution of this research is to a reduction in delay and optimized energy solution,a novel hybrid model design in this research that ensures the quality of service in WSN.This model includes a whale optimization technique that involves heterogeneous functions and performs optimization to reach optimized results.For cluster head selection,Stable Election Protocol(SEP)protocol is used and Power-Efficient Gathering in Sensor Information Systems(PEGASIS)is used for driven-path in routing.Simulation results evaluate that H-LEACH provides minimal delay and energy consumption by sensor nodes.In the comparison of existing theories and our proposed method,HLEACH is providing energy and delay reduction and improvement in quality of service.MATLAB 2019 is used for simulation work.

Regulation of excitation energy transfer in Sb-alloyed Cs_(4)MnBi_(2)Cl_(12) perovskites for efficient CO_(2) photoreduction to CO and water oxidation toward H_(2)O_(2)

Lead(Pb)-free halide perovskites have recently attracted increasing attention as potential catalysts for CO_(2) photoreduction to CO due to their potential to capture solar energy and drive catalytic reaction.However,issues of the poor charge transfer still remain one of the main obstacles limiting their performance due to the overwhelming radiative and nonradiative charge-carrier recombination losses.Herein,Pb-free Sb-alloyed all-inorganic quadruple perovskite Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12)(0≤x≤1)is synthesized as efficient photocatalyst.By Sb alloying,the undesired relaxation of photogenerated electrons from conduction band to emission centers of[MnCl6]^(4-)is greatly suppressed,resulting in a weakened PL emission and enhanced charge transfer for photocatalyst.The ensuing Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12) photocatalyst accomplishes efficient conversion of CO_(2)into CO,accompanied by a surprising production of H_(2)O_(2),a high valueadded product associated with water oxidation.By optimizing Sb^(3+) concentration,a high CO evolution rate of 35.1μmol g^(-1)h^(-1)is achieved,superior to most other Pb and Pb-free halide perovskites.Our findings provide new insights into the mixed-cation alloying strategies for improved photocatalytic performance of Pb-free perovskites and shed light on the rational design of robust band structure toward efficient energy transfer.

The Five-Year Plan: A new tool for energy saving and emissions reduction in China

China has achieved economic growth while great carbon emissions reduction in recent years. Amid China＇s effort to reduce emissions, the Five-Year Plans have guided and motivated local and foreign forces from the government, industries, and society to work together. This paper showed that a mediumehigh economic growth gate, industry structure adjustment, and energy structure adjustment, which are guaranteed under the Five-Year Plan, all contribute to energy saving in China. The economy entered a stable growing phase during the 12 th Five-Year Plan, while the economic growth rate declined to 7.8% from 11.2% in the 11 th Five-Year Plan. Simultaneously, the CO2 emissions growth rate declined from8.32%（2009-2012 mean） to 1.82%（2012-2014 mean）. Industrial structure adjustment canceled out nearly one-third of the CO2 emissions caused by economic growth. Under the 13 th Five-Year Plan, China will continue its energy saving efforts on the green development path, with greener quotas, a stricter implementation process, and more key projects.

Utilization of Livestock's Dejection as Biogas Origin in Building New Countryside in Heilongjiang Province--Developing Utilization of Biogas and Promoting Energy-saving and Emission Reduction

With the startup and execution of new socialistic countryside construction in Heilongjiang Province,the transition from castoff to resource is strengthened in the countryside,aiming at neat appearance of the countryside,clean production and saving energy.People produce biogas and provide the countryside with new energy by means of turning livestock＇s dejection into resources,composting of the plant and animal＇s leavings in the courtyard and even in the factory.It is helpful for the countryside to conserve the energy and reduce emission of the waste.And it also plays an important role in protecting the eco-environment,beautifying homestead and developing the ecological agriculture and so on.The liquid and solid residue in the biogas production can be reused as fertilizer for crops or food for animals after pretreatment,which is propitious to accelerate the development of the circular economy in Heilongjiang Province.

Energy Saving and Emission Reduction Estimations of Electrified Railways in China

Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.

Summary of Steam System Optimization and Energy Saving and Carbon Reduction Practice in Yanshan Petrochemical Company

This paper analyzes the main problems of Sinopec Beijing Yanshan Petrochemical Co.,Ltd.,such as decentralized steam system layout,many types of fuels,obvious increase in fuel cost,low operation efficiency of turbine and boiler and high self consumption loss,and puts forward and implements optimization and improvement measures such as pressure raising transformation of natural gas system,adjustment of energy consumption structure,reduction of energy consumption cost,improvement of steam production quality and equipment efficiency.The results showed that compared with the fuel consumption in 2018,the consumption of coal coke was reduced by 550000 t,the consumption of natural gas was increased by 170000 t,and the total consumption of fuel gas and fuel oil was increased by 50000 t,equivalent to 246000 t of standard coal;the purchased electricity was increased by about 5×10^(8) kW·h.Green power trading and 14.76 MW distributed photovoltaic projects were carried out.According to the calculation of 1400-1600 h annual power generation in class II photovoltaic areas and the emission factor of North China regional power grid baseline,the annual emission reduction was about 55000 t CO_(2) in 2021.After the above transformation,the goal of zero-coking is achieved;the steam consumption of units is reduced by 21.5%,the steam production of boilers is reduced by 24.9%,and the annual emission reduction is about 760000 t CO_(2),which has achieved good results.

Case Studies of Energy Saving and CO₂Reduction by Cogeneration and Heat Pump Systems

This paper describes two case studies: 1) a cogeneration system of a hospital and 2) a heat pump system installed in an aquarium that uses seawater for latent heat storage. The cogeneration system is an autonomous system that combines the generation of electrical, heating, and cooling energies in a hospital. Cogeneration systems can provide simultaneous heating and cooling. No technical obstacles were identified for implementing the cogeneration system. The average ratio between electric and thermal loads in the hospital was suitable for the cogeneration system operation. An analysis performed for a non-optimized cogeneration system predicted large potential for energy savings and CO2 reduction. The heat pump system using a low-temperature unutilized heat source is introduced on a heat source load responsive heat pump system, which combines a load variation responsive heat pump utilizing seawater with a latent heat-storage system (ice and water slurry), using nighttime electric power to level the electric power load. The experimental coefficient of performance (COP) of the proposed heat exchanger from the heat pump system, assisted by using seawater as latent heat storage for cooling, is discussed in detail.

Energy savings and CO_2 emission reduction by using geothermal heat pumps

The renewable energy will play significant role in the world primary energy consumption in the future. Geothermal energy is immense with 5 000 EJ/a of technical potential, and geothermal heat pumps (GHPs) are one of the fastest growing applications of renewable energy in the world with annual increases of 10 % and much faster in China. With high coefficient of performance (COP) up to 6, GHPs make efficiency of primary energy more than 240 % with assumed a 40 % of electricity generation efficiency, which means energy savings and CO2 emission reduction. In this paper,the geothermal resources and its utilization are talked about, and GHPs technology was introduced. Due to its high efficiency, there will be energy savings by using GHPs. There is also CO2 emission reduction because of using geothermal heat pumps, which is analyzed in the end.

An Approach to Energy Saving and Cost of Energy Reduction Using an Improved Efficient Technology

The electricity consumption in commercial places like universities has tremendously increased recently. Modern and advanced energy efficient appliances are highly needed to substitute the conventional ones. Energy saving is of great important instead of its wastage, as utilizing the energy efficiently reduces the cost of energy. Energy consumption varies for commercial building due to several factors such as electrical appliance usage, electrical appliance type, management, etc. Due to the advancement in technology, there are new emergence appliances that are of high efficiency and have less energy consumption. A case study is conducted on selected five tutorial rooms, level 4 buildings in the Faculty of Electrical Engineering 19 A, Universiti Teknologi Malaysia. The paper proposes new emergence equipments with high efficiency and less power consumption to replace the existing ones. A survey is conducted on the number of electrical appliances used for each of the tutorial rooms, time table for each tutorial room and the Tenaga Nasional Berhad pricing and tariff are taken into consideration in the analysis of the energy consumption and the cost of energy. This paper aims at reducing the amount of energy consumption by replacing the existing electrical equipments with high efficient electrical equipments;it also tends to reduce the cost of energy paid to the utility. By observing the results, it shows that the proposed efficient electrical equipments are more efficient, less power consumption and less cost compared to the existing electrical equipments.

Energy Saving and Pollutant Reduction: Nuclear vs Thermal

This paper presents the development status of thermal and nuclear power industries in China in recent years. It makes a comparison between the two industries from the aspects of reliability, economics, energy saving and pollutant reduction, by which the effects of expanding nuclear power on pollution control, resources conservation and eff icient energy use are evaluated, and several points of view are summarized.

China's Wind Power Integration and Benefits to Energy Saving and Emission Reduction

Based on the research of wind power development policies, this paper put forward the reform directions to improve the disadvantages of the policies. The wind power’s grid integration status quo is introduced, and the bottle neck of grid integration is analyzed. By the study on the economic benefits of wind power integration in China’s present stage, the results indicate that the wind power industry is in good condition of profits and the profits are higher with the increase of the wind resources in the areas. Through expanding the difference of the power purchase prices in different resource areas, it is beneficial for the nationwide harmonious development of wind power. At last, the present and future benefits of the energy conservation and emission reduction from wind power integration are estimated, which shows that the environmental benefits of "wind-thermal exchange" will be more and more outstanding along with the expansion of the scale of wind power.

A research of green taxation policy for promoting energy saving and emission reduction

It's been proved by theory and practice that taxation policy is one of the important means of realizing energy saving and emission reduction. The green taxation system in the Western countries has got better effects in energy saving and environmental protection. In the recent years, China has in succession released some taxation policies promoting energy saving and emission reduction, but still has a huge gap to meet the real needs of energy saving and emission reduction. By analyzing China's status quo of the polices of energy saving and emission reduction and drawing upon experiences of the developed countries about green taxation, this paper presents how to perfect ideas of China's energy saving and emission reduction taxation policies: adjusting taxes relevant to green taxation in the current taxation system, such as resource tax, consumer tax, and so on; collecting new environmental tax; perfecting the preferential taxation policies for the energy saving and environmental protection industries.

The development of slag processing technology and its impact on energy-saving and emission reduction in the metallurgical industry

This study provides an overview of the production and classification of metallurgical slag and its impact on energy-saving and emission reduction in the metallurgical industry and an analysis of the impact of key factors on slag processing technology, including a brief account of blast furnace（BF） slag processing and applications with a focus on the steel slag disposal processes and the features of some typical processes. In view of the characteristics of the basic oxygen furnace （BOF） slag and the technical difficulties faced by the traditional processes,it describes the principle,features and technical advantages of the Baosteel short-flow （BSSF） steel slag treatment process developed by Baosteel. The thinking and outlook on the direction of the development of the metallurgical slag processing process are stated.

Rational catalyst design and mechanistic evaluation for electrochemical nitrogen reduction at ambient conditions

Ammonia(NH3), a carbon-free hydrogen carrier, is an important commodity for the food supply chain owing to its high energy capacity and ease of storage and transport. The Haber-Bosch process is currently the favored industrial method for large-scale ammonia production but requires energy-intensive and sophisticated infrastructure which hampers its utilization in a sustainable and decentralized system of manufacture.The electrochemical nitrogen reduction reaction(eNRR) at ambient conditions holds great potential for sustainable production of ammonia using electricity generated from renewable energy sources such as solar and wind. However, this approach is limited by a low rate of ammonia production with high overpotential and the competing hydrogen evolution reaction(HER). For a better understanding and utilization of eNRR as a sustainable process, insight into rational catalyst design and mechanistic evaluations by a theoretically-directed experimental approach is imperative. Herein, recent insights into rational catalyst design and mechanisms, based on intrinsic and extrinsic catalytic activity are articulated.Following the elucidation of basic principles and mechanisms, a framework supplied by theoretical studies that lead to the optimal selection and development of eNRR catalysts is presented. Following a discussion of recently developed electrocatalysts for eNRR, we outline various recently-used theoretical and experimental methodologies to improve the intrinsic and extrinsic catalytic activity of advanced electrocatalysts.This review is anticipated to contribute to the development of active, selective, and efficient catalysts for nitrogen reduction.

Energy conservation and emissions reduction strategies in foundry industry

Current energy conservation and emissions reduction strategies in iron and steel industry were reviewed. Since foundry industry is one of the major source of energy consumption and pollution emission (especially CO 2 ), issues concerning energy-saving and emission-reduction have been raised by governments and the industry. Specialists from around the world carried out multidimensional analyses and evaluation on the potentials in energy conservation and emissions reduction in iron and steel industry, and proposed various kinds of analyzing models. The primary measures mainly focus on the targeted policies formulation and also on clean and highefficient technologies development. The differences and similarities in energy conservation and emission reduction in foundry industry between China and other countries were discussed, while, the future development trend was also pointed out.

Impacts of optimization strategies on performance,power/energy consumption of a GPU based parallel reduction

In the era of modern high performance computing, GPUs have been considered an excellent accelerator for general purpose data-intensive parallel applications. To achieve application speedup from GPUs, many of performance-oriented optimization techniques have been proposed. However, in order to satisfy the recent trend of power and energy consumptions, power/energy-aware optimization of GPUs needs to be investigated with detailed analysis in addition to the performance-oriented optimization. In this work, in order to explore the impact of various optimization strategies on GPU performance, power and energy consumptions, we evaluate performance and power/energy consumption of a well-known application running on different commercial GPU devices with the different optimization strategies. In particular, in order to see the more generalized performance and power consumption patterns of GPU based accelerations, our evaluations are performed with three different Nvdia GPU generations(Fermi, Kepler and Maxwell architectures), various core clock frequencies and memory clock frequencies. We analyze how a GPU kernel execution is affected by optimization and what GPU architectural factors have much impact on its performance and power/energy consumption. This paper also categorizes which optimization technique primarily improves which metric(i.e., performance, power or energy efficiency). Furthermore, voltage frequency scaling(VFS) is also applied to examine the effect of changing a clock frequency on these metrics. In general, our work shows that effective GPU optimization strategies can improve the application performance significantly without increasing power and energy consumption.