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Development of Uv-Visible Light Active Photocatalysts for Hydrogen Production from Renewable

Thesis Info

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Author

Majeed, Imran

Supervisor

Muhammad Arif Nadeem

Program

PhD

Institute

Quaid-I-Azam University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2017

Thesis Completion Status

Completed

Subject

Inorganic/Analytical Chemistry

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/10208/1/Imran%20Majeed_Inorganic%2c%20Analytical%20Chem_2017_QAU_PRR.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725893320

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The development of the “hydrogen economy” requires new technologies for H2 generation, of which photocatalytic water splitting by using visible light has been viewed as most promising pathway. In present study, the photocatalysts ranging from simple metal oxides and metal sulfides to more complicated systems have been studied to achieve suitable H2 production rates from water splitting reaction The hydrogen production from water in the presence of other renewable (ethanol, glycerol, triethanolamine and ethanol water-electrolyte mixtures) were studied over three different semiconductor (TiO2, CdS and an emerging g-C3N4) supports based photocatalysts. All the synthesized catalysts were characterized by various analytical techniques such as Powder X-ray Diffraction (PXRD) for determination of crystal phase composition and purity, X-ray Photoelectron Spectroscopy (XPS) for surface elemental composition, Diffused Reflectance UV-visible Spectroscopy (DRS) for optical properties, Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy for particle size distribution and morphology, Photoluminescence (PL) for electron dynamics, Energy dispersive spectroscopy (EDS), Inductively Coupled Plasma Optical Emission spectroscopy (ICP-OES) and X-ray Fluorescence (XRF) for elemental composition, Brunauer Emmett Teller (BET) for surface area calculation and Thermogravimetric analysis (TGA) to study changes in physical and chemical properties of materials as a function of temperature. Hydrogen production for each photoreaction was measured by Gas Chromatograph (GC) equipped with molecular sieve capillary column and TCD detector. In the first section, a series of novel non-noble metal supported semiconductor photocatalysts; Cu(OH)2– Ni(OH)2/P25 (P25=80% anatase +20% rutile) and Cu(OH)2–Ni(OH)2/TNR (TNR = Titania nanorods) were prepared by co-deposition–precipitation method (total metal loading ca. 1.0 wt%) and their performance was evaluated for H2 production. Among this series, the 0.8Cu(OH)2–0.2Ni(OH)2/P25 photocatalyst showed H2 production rate of 10 and 22 mmol h‒1g‒1, in 20 vol% ethanol-water and 5 vol% glycerol-water mixtures, respectively. The 0.8Cu(OH)2–0.2Ni(OH)2/TNR photocatalyst demonstrated very high H2 production rates of 26.6 and 35.1 mmol h‒1g‒1 in 20 vol% ethanol-water and 5 vol% glycerol-water mixtures, respectively. The mechanism for high hydrogen production rate over bimetallic hydroxide supported TiO2 is investigated and established with various experimental evidences. Followed by this, a new strategy was developed to produce highly dispersed Cu and Cu2O nanoparticles over TiO2 by using MOF-199 [Cu3(BTC)2(H2O)3]n as a source of copper nanoparticles. The photocatalyst 1 wt% Cu/TiO2-400 showed a hydrogen production rate vii some 2.5 times higher than that of CuO deposited over TiO2 by conventional precipitation methods. In the second section, highly crystalline and photocatalytically active hexagonal CdS nano-support was synthesized by sol-gel method and subsequently calcination in an inert atmosphere of nitrogen. Au nanoparticles were deposited over this hexagonal CdS by a novel reductive deposition KI method involving reduction of Au3+ ions with iodide ions and used as a model to test the effect of metal particle size as well as the reaction medium on hydrogen production activity. The photocatalyst 3 wt.% Au/CdS showed the highest performance (ca. 1 molecule of H2/AuatomS−1) under visible light irradiation from water electrolyte medium (0.1M Na2S–0.02 Na2SO3; pH 13) (92%)—ethanol (8%). The validity of this new Au loading method was established by comparing it with three other conventional methods including; deposition precipitation (DP), incipient wet impregnation (WI) and photo-deposition (PD). TEM studies of fresh and used catalysts showed that Au particle size increases (almost 5 fold) with increasing photo-irradiation time due to photo-agglomeration effect and yet no sign of deactivation was observed. A mechanism for hydrogen production from ethanol waterelectrolyte mixture is presented and discussed by evaluating some intermediate formed. It is found that Au/CdS photocatalyst showing higher plasmonic effect did not necessarily produced more hydrogen in visible light range. This work also supports the electron transfer mechanism from semiconductor to metal which may further be facilitated by metal to semiconductor energy transfer mechanism due to Au surface plasmon resonance. Finally, in third section, g-C3N4 was synthesized by thermal condensation of melamine at various temperatures to get close packing and strong interlayers binding of g-C3N4. Pd and Ag bimetallic as well as monometallic nanoparticles were deposited to cope with two inherent drawbacks of g-C3N4; low visible light absorption and high recombination rate of photogenerated charge carriers. High activity of Pd-Ag/g-C3N4 photocatalyst was attributed to inherent property of palladium metal to quench photogenerated electrons by schottky barrier formation mechanism and strong silver absorption in visible range by surface plasmon resonance mechanism (SPR).
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حمدو نعت

دیوانِ یونس فریدی
حمد و نعت
صد شکر سوچ میری بھی تبدیل کچھ ہوئی
صد شکر میرے دل کو بھی ارمانِ نعت ہے
ٰ
حمد

وہ ہے قادر، نہیں ہے اس میں کلام
اُس کے محتاج سب خواص و عوام

وہ سجھائے کمال کی جہتیں
ہے نا! انسان ہر لحاظ سے خام

جا رہا ہے ہر ایک مر کر بھی
باندھ کر جسم پر سفید احرام

ڈھانپ لے گی گناہ گاروں کو
رحمتِ ذوالجلال والا کرام

اے خدائے کریم! یونسؔ پر
رہے قائم سدا ترا انعام

نعت

منبعِ جود و سخا ہے، اُنؐ کی ذات
بے نواؤں کی نوا ہے اُنؐ کی ذات

اُنؐ کی آمد پر ہوا حق کا ظہور
مظہرِ نورِ خدا ہے اُنؐ کی ذات

امتوں میں اُنؐ کی امت ذی وقار
تاج دار انبیا ہے اُنؐ کی ذات

دیدہ ور ہو، آزما کر دیکھ لو!
آج بھی جلوہ نما ہے اُنؐ کی ذات

کیا کرے یونسؔ کوئی اُنؐ کی ثناء
عقل سے بھی ماورا ہے اُنؐ کی ذات
ز
آمدِ خیرالوریٰ، صد مرحبا

خود خدا محو ثنائ، صد مرحبا
نعت گوئی میں ہمارے مقتدی

طائران خوش نوا، صد مرحبا
جن و انساں وجد میں ہیں اک طرف

اک طرف ارض و سما، صد مرحبا
ہے فرشتوں کی زباں پر آج بھی
مرحبا صلی علی، صد مرحبا
ز
اگر درپیش کوئی مسئلہ ہو

نظر سوئے درِ خیرالوریٰؐ ہو
اجل بھی رشک سے دیکھے گی مجھ کو

زباں پر اُس گھڑی یا مصطفٰےؐ ہو
ملے اِذنِ زیارت، اور پھر

وفور شوق میں دل...

معاشرتی فساد و انتشار کے تدارک کا نبوی منہج

Islam provides a complete code of life and no doubt it is the religion of love and peace. The aim 0f its teaching is to unite the Muslim world specially and the whole human community in general. “Prophetic Methodology for the Elimination of Social Disturbance and Anarchy” is the topic to provide the practical guideline to built a peaceful and human caring society. First of all the word disturbance and anarchy has been described, secondly the kinds of disturbance and anarchy as internal and external has been discussed. Different aspects, reasons and the solutions of all external and internal disturbance and anarchy has been discussed in detail. Moreover their targets and objectives have also been expressed. The main focus of the research is to provide the practical solution of all types of social disturbance and anarchy in light of Prophetic teachings.

Development of Relationships Among Vehicular and Driver’S Characteristics With Traffic Accidents

The city of Lahore is the provincial headquarter of the Punjab province. Lahore has different types of traffic as compared to other cities of Pakistan. The old areas have mixed traffic and the outskirt areas have fast moving traffic. The main factors for traffic accidents are roads, vehicles, drivers, external factors and enforcement by traffic police. The riding quality of roads of Lahore is normal. The external factors such as weather condition in Lahore are not so severe as to cause accidents. The condition of vehicles especially public transport fleet, plying on the roads of Lahore, is alarming as periodic maintenance of vehicles is not frequently carried out. The literacy rate of the country is also an issue. Most of the drivers, especially drivers of public transport vehicles, are not educated. They have problems in understanding the traffic rules, signs and signals. In such a situation their behaviour while driving is unsafe and they come across traffic accidents associated with human losses, human sufferings and economic losses. Considering these facts into account it was planned to study the drivers and vehicles characteristics with special reference to their role towards traffic accidents. The basic objective of this research was to develop Accident Prediction Models (APMs) relating number of accidents occurred per year and to know the causes of accidents of different vehicle types based on the vehicular and driver’s characteristics. By knowing the causes of accidents, another purpose was to suggest some measures to lessen the number of accidents. In this regard, questionnaire/survey forms comprising about 107 vehicular and driver’s characteristics were prepared after going through the world wide relevant literature. Seven types of vehicles were selected for the study and for each vehicle type survey was conducted on different locations of Lahore to collect representative information regarding vehicular and driver’s characteristics including number of traffic accidents experienced. The survey locations were chosen on the basis of most probable presence of different vehicle types within Lahore. The types of vehicles considered for this research study include Motorcycle Rickshaw (Qingqi), Motorcycle, Passenger Car, Wagon, Bus, Auto Rickshaw and Pickup. Representative and justified sample sizes were selected using stratified sampling technique on the basis of number of registered vehicles for each type. Statistical package for social sciences (SPSS) was used for analysis of the characteristics. Frequency, correlation and cross-tabulation analyses were conducted for each vehicle. On the basis of these analyses, the most significant driver’s and vehicular characteristics contributing traffic accidents were identified for each vehicle type. With these most significant characteristics, APMs using the multiple linear regression analysis relating the number of accidents per year were developed for all seven types of vehicles. The APMs developed can be used to assess the number of accidents per year for seven types of vehicles on the basis of their vehicular and driver’s characteristics for each vehicle type. On the basis of developed APMs, it is concluded that the main contributing factors towards accidents are vehicular and driver’s characteristics. So it is recommended that by properly addressing the vehicular and driver’s characteristics, incidents of traffic accidents can be reduced.