Ni-Cr-Cu三元合金电极制备及其析氢性能研究

以废旧紫铜片为基体,Ni粉、Cr粉为覆膜材料,通过活化反应烧结法制备了Ni-Cr-Cu三元合金电极材料。采用X射线衍射分析(XRD)、场发射电镜(SEM)、能谱(EDS)等对电极的物相、形貌结构、元素分布以及析氢产物进行表征;通过循环伏安、线性极化、交流阻抗等方法测试了合金电极材料的电催化析氢性能。结果表明,Ni-Cr-Cu三元合金薄膜电极具有优异的析氢性能,调节Cr元素的含量可提高其析氢催化活性,在室温条件下,Ni30%Cr-Cu三元合金电极材料在6 mol/L KOH的溶液中析氢性能较好,其析氢过电位仅有-0.13 V (vs RHE),交换电流密度为10 mA/cm~2时对应的极化电位为-0.145 V (vs RHE);经开路电位测试36 000 s后,电极材料的开路电位(η)从0.05 V变化为0.02 V,仅降低0.03 V,表明析氢电极化学稳定性良好。     

Ni-Co合金的制备及其析氢电催化性能

通过真空熔炼与固溶处理相结合的方法获得Ni_(30)Mn_(70)和Ni_(20)Co_(10)Mn_(70)前驱体合金,利用电化学脱合金化法制备纳米多孔Ni及Ni-Co合金,采用X射线衍射(XRD)、扫描电子显微镜(SEM)分析合金相组成和微观结构,运用线性扫描伏安法、交流阻抗、方波电位法及计时电位法研究电极的析氢电催化性能。结果表明:Co的加入与Ni形成协同效应,能够有效提高合金电催化活性,且在一定程度上提高了纳米多孔Ni的电化学稳定性。Ni_(20)Co_(10)Mn_(70)制得的纳米多孔Ni-Co合金表面积是纳米多孔Ni的1.609倍,在0.1 A/cm~2电流密度下,析氢过电位仅128 m V,经10 h连续电解,表现出良好的析氢电催化活性及电化学稳定性。     

多孔Ni-Cu-Ti-La2O3复合电极的制备及其析氢性能

采用粉末冶金方法烧结制备了多孔Ni-Cu-Ti-La₂O₃复合电极,讨论不同La₂O₃的掺杂量对电极析氢性能的影响。利用X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等测试手段对电极的微观结构和物相组成进行表征。结果表明：Ni-Cu-Ti合金体系中La₂O₃的掺杂可有效提高电极材料的电荷传输速率,多孔Ni-Cu-Ti-La₂O₃复合电极在6 mol/L KOH溶液中表现出良好的析氢催化活性,其整体析氢催化活性明显优于多孔Ni-Cu-Ti、Ni-Cu-W、Ni-Cu-Co、Ni-Cu-Zr和Ni-Cu电极;当烧结温度为1000℃时,成分为Ni-CuTi-9La的多孔复合电极具有最佳的析氢催化性能,其Tafel斜率为63.18 mV/dec,电流密度在10 mA/cm²时过电位为1077 mV(vs Hg/HgO),多孔Ni-Cu-Ti-La₂O₃     

Ni/LaNi5多孔复合电极的制备及其析氢电催化性能

先电沉积Ni-Zn合金镀层,然后用浓碱将镀层中的锌脱溶,得到多孔镍,最后采用复合电沉积将LaNi5镶嵌到多孔镍表面,制备成Ni/LaNi5多孔复合电极。采用稳态极化曲线和交流阻抗谱对电极的电催化析氢性能进行了评价,并运用恒电位间歇电解和长时间电解,开路电位等研究了电极的电析氢稳定性。结果表明:Ni/LaNi5多孔复合电极的析氢表观交换电流密度分别是镍和多孔镍的172倍和26倍;多孔复合电极中的LaNi5具有稳定电极的作用,该电极比多孔镍具有更优异的抗断电性能。     

泡沫基材-Ni-石墨烯复合镀层制备及电催化析氢性能研究

目的 采用电沉积技术在泡沫基材上沉积制备Ni-石墨烯复合镀层,期望借助泡沫基材的三维多孔结构和石墨烯的超高比表面积来改变复合材料的表面状态,进而获得高镀层的电催化析氢性能。方法 采用电沉积技术将石墨烯作为第二相粒子沉积,制备了泡沫基材-Ni-石墨烯复合电极,通过SEM和EDS研究了其微观形貌及成分,并利用电化学工作站完成了镀层电极的极化曲线、交流阻抗和电解水稳定性测试,使用控制变量法探究了镀层厚度、镀液石墨烯浓度和基材形貌对镀层电催化析氢活性的影响。结果 SEM和EDS表征发现,镀层表面形貌受镀液中石墨烯浓度影响较大,石墨烯作为第二相嵌入镀层后,明显改变了复合镀层的表面形貌,其存在形态为颗粒状,在150 mg·L^–1时颗粒堆积最多。进一步利用电化学分析技术探究了镀层厚度、镀液石墨烯浓度和基材形貌对电极电催化析氢性能的影响,发现在一定范围内,不同厚度镀层的电催化析氢活性基本相同;石墨烯质量浓度为150mg·L^–1时制得的电极的电催化析氢性能最优,析氢过电位为211.2m V(vs.RHE),且电解水稳定性良好;泡沫基材镀层的电催化析氢活性明显优...     

镍基析氢电极在碱性溶液中析氢行为

采用元素粉末反应合成法制备多孔Ni_3Al-Mo电极。采用扫描电镜(SEM)和X射线衍射(XRD)对多孔Ni_3Al-Mo电极的孔结构进行表征,通过极化曲线和电化学阻抗技术表征多孔Ni_3Al-Mo电极的电解析氢行为。结果表明:多孔Ni_3Al-Mo电极孔隙率为47%,最大孔隙为2.7μm,平均孔隙约2.1μm。与多孔Ni_3Al电极和多孔Ni电极相比,多孔Ni_3Al-Mo电极具有较低的析氢过电位和较高的交换电流密度,表明多孔Ni_3Al-Mo电极具有较高的析氢活性;经过阳极处理后,多孔Ni_3Al-Mo电极的析氢活性可以恢复到原来的大小,且连续电解120 h后,析氢过电位变化不大,表明多孔Ni_3Al-Mo电极具有优异的电化学稳定性。     

新型Nd掺杂PbO_2阳极性能及对AOII的电催化氧化作用

采用电沉积法制备了稀土金属Nd改性Pb O_2电极(Nd-Pb O_2),并通过扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、荧光光谱(FP)、线性极化扫描(LSV)、强化寿命测试(ALT)、循环伏安扫描(CV)等方法表征了其表面结构和电化学性能,探讨了对酸性橙II(AOII)的电催化氧化性能。SEM、XRD、XPS测试结果表明,Nd以Nd~(3+)形式掺杂进入电极镀层,同时对表面形貌、元素组成均有不同程度的改变,但不改变镀层表面的β-Pb O_2晶型;电化学性能测试表明,Nd掺杂可有效提高电极的析氧电位和稳定性;CV测试及AOII降解实验结果表明,Nd-Pb O_2电极对AOII还表现出直接氧化作用,电催化氧化AOII能力更强;FP分析表明,Nd-Pb O_2具有较强的催生羟基自由基能力,可增强电极降解有机物的催化活性。     

电沉积Ni-Fe-P非晶合金析氢阴极材料及其去合金化处理

目的 提高Fe电极的催化析氢性能。方法 较低温度条件下,在Fe基体表面电沉积一层非晶态Ni-Fe-P镀层,探究沉积电流密度、去合金时间等参数对Ni-Fe-P/Fe电极在碱性电解质中的电催化析氢反应的影响。通过扫描电镜、能谱、X射线衍射对镀层的形貌、元素分布、物相进行分析。在碱性溶液中,利用电化学工作站对电极进行一系列性能测试。结果 在沉积温度为10 ℃的条件下,于Fe电极表面成功制备出了致密且元素分布均匀的Ni-Fe-P非晶合金镀层。获得的Ni-Fe-P/Fe电极电催化性能均优于Fe电极,其中电流密度30 mA/cm2条件下制备的Ni-Fe-P/Fe电极在析氢电流密度为10 mA/cm2时的过电位为174.2 mV,比Fe电极低约466.2 mV。在相同条件下制备的Ni-Fe-P/Fe电极,经240 s去合金化处理,电极过电位仅为121.6 mV,比Fe电极低约518.8 mV。结论 电沉积的Ni-Fe-P非晶合金镀层可以显著提高Fe电极的析氢性能。随着沉积电流密度的增加,Ni-Fe-P/Fe电极的析氢过电位减小,双电层电容和电化学工作表面积增大。对镀层进行适当的去合金化处理,形成的三维多孔结构可以减小电极的电荷转移电阻,有效降低电极的析氢过电位。     

Al-Ga-Mg-Sn-xZn阳极合金组织和腐蚀电化学性能

对不同Zn含量的Al-Ga-Mg-Sn-xZn系列阳极合金的组织及腐蚀形貌进行观察和分析,并测试了该系列合金在4 mol/L NaOH溶液中的析氢速率、开路电位、极化曲线等腐蚀电化学性能指标,研究了Zn对Al-Ga-Mg-Sn合金组织和腐蚀电化学性能的影响。结果表明:Al-0.1Ga-1Mg-0.1Sn-xZn合金中的析出相主要为富Sn相,合金元素Zn主要固溶于Al基体中,添加0.5%和1%(mass%)的Zn后,合金的耐蚀性提高,开路电位和恒电流放电工作电位均有所负移,Al-0.1Ga-1Mg-0.1Sn-1Zn合金的综合腐蚀电化学性能较好,在4 mol/L NaOH溶液中,稳定开路电位约-1.72 V(vs.Hg/HgO),析氢速率为0.202 mL·cm-2·min-1,100 mA·cm-2放电时工作电位达-1.41 V(vs.Hg/HgO),腐蚀形貌均匀。     

氨络合物体系中Ti基IrO2涂层阳极的析氮过程

采用线性扫描技术研究了氯盐氨络合物体系中Ti基IrO2涂层阳极的析氮过程,对3种含有不同氧化物涂层电极的析氮电催化性能进行了比较,并结合扫描电镜(SEM)及能谱(EDX)探讨了不同析氮电催化活性的原因.研究结果表明:当电极电位低于1.1 V(vs SCE)时,Ti基IrO2涂层阳极析气反应主要为析氮反应,氮气的产生主要是由于氨水在电极上发生电化学氧化引起的;Ti基含PdRuTi的IrO2涂层阳极具有最佳的析氮电催化活性,其可能原因是金属元素PdRuTi的存在导致该电极表面特征裂纹最宽且最深,氧化物涂层总析氮面积增多,电催化活性增加.     

Effect of surface free energy of acetylene black powder on air electrode performance

The effects of acetylene black powder surface free energy on air electrode electrochemical performance and lifetime were studied. The acetylene black was immersed in 30% H2O2 at room temperature and the changes of functional groups and surface free energy were investigated by X-ray Photoelectron Spectroscopy (XPS) and powder contact angle (CA). The air electrode performance was characterized by the potential polarization curves and the lifetime was measured by constant-current discharge. It shows that, its surface free energy is the lowest when the acetylene black is immersed in H2O2 for 240 h. The polarization potential of the air electrode prepared by the pretreated acetylene black is 0.25 V(vs. Hg/HgO), 0.21 V lower than the air electrode with untreated acetylene black when the working current density is 100 mA·cm-1 . And its lifetime is over 800 h at 80 mA·cm-1 . The pretreatment of acetylene black for proper time by H2O2 is favorable for the stability of the tri-phase reaction interface of air electrode and improvement of its performance.     

Preparation of CuS/BiVO_4 thin film and its efficacious photoelectrochemical performance in hydrogen generation

To drive photoelectrochemical water splitting on porous BiVO_4 photoanode, we herein prepared a carnationlike CuS powder by hydrothermal method and then loaded it onto BiVO_4 photoelectrode. Expectedly, the CuS/BiVO_4 composite not only presents a higher photocurrent response value at 1.23 V versus RHE(reversible hydrogen electrode) than pure BiVO_4 electrode under visible light irradiation, but also exhibits an excellent photoelectrochemical hydrogen production activity in comparison with either the BiVO_4 or the CuS. The high ameliorated performance of CuS/BiVO_4 composite may be due to the strong absorption of visible light and an effective abatement in combination of carriers. These results demonstrate an effective potential approach to design and construct efficient photoelectrochemical(PEC) systems.     

Electrocatalytic performance of Pb−Ru pyrochlore prepared by the amorphous citrate precursor method for bifunctional air electrodes

Pb−Ru pyrochlore has been of interest as bifunctional electrocatalyst for an air electrode. An amorphous citrate precursor (ACP) process has been optimized to prepare Pb−Ru pyrochlore powders with high surface areas with consequent improvement of its electrocatalytic performance in an air electrode. The surface area of the final powder is 30 m²/g, which is larger than the value obtained by the conventional hydroxide method. A PTEF-bonded gas diffusion electrode loaded with pyrochlore catalysts prepared by the ACP method showed good bifunctional performance. The electrode loaded with only 10 mg/cm² of pyrochlore powder prepared by ACP showed good bifunctional performance, i.e. 100 mA/cm² for oxygen reduction and 100 mA/cm² for oxygen evolution, at 0.6 and 1.6 V vs. RHE, respectively. This performance compares well to the results from lower-area pyrochlore at much higher loading.     

阴极极化对高强度船体结构钢焊缝氢脆敏感性的影响

在恒定阴极电位下利用慢应变速率拉伸试验研究高强度船体结构钢焊缝的电化学性能和力学性能。结果表明,试样拉伸断裂主要发生在焊缝的熔合区;结构钢的阴极极化程度对抗拉强度和屈服强度的影响不大;随阴极电位负移,船体结构钢在海水中的延伸率、断裂时间和断裂应变率逐渐减小, 并且当施加阴极电位为-0.89 V（vs SCE）时各项性能最佳。同时,随着阴极电位负移,断裂方式逐渐从韧性断裂向脆性断裂发展,氢脆敏感性逐渐增加,在 -0.70 V~-0.89 V（vs SCE）之间氢脆敏系数低于5%,不发生氢脆;当电位负于-0.94 V（vs SCE）,氢脆敏感性迅速提高,当极化电位为-0.99 V （vs SCE）时氢脆系数显著增大至20%,断口开始出现解理单元细小准解理断裂特征;在负于-1.04 V（vs SCE）时,氢脆系数已高于25%,进入危险区,且断口开始出现较多解理单元粗大的准解理、解理等氢脆断裂特征;随着电位继续负移至-1.14 V（vs SCE）,断口完全出现解理组织、沿晶、穿晶结构或者两者混合的氢脆断裂特征。     

Effect of rolling processing on microstructure and electrochemical properties of high active aluminum alloy anode

The effect of rolling processing on the microstructure,electrochemical property and anti-corrosion property of Al-Mg-Sn-Bi-Ga-In alloy anode in alkaline solution(80℃,Na2SnO3+5 mol/L NaOH)was analyzed by the chronopotentiometry (E-T curves),hydrogen collection tests and modern microstructure analysis.The results show that when the rolling temperature is 370℃,the electrochemical activity of Al anode decreases gradually with the increase of pass deformation in rolling,while the anti-corrosion property is improved in the beginning and then declined rapidly.When the pass deformation of rolling is 40%,the Al anode has good electrochemical activity as good as the anti-corrosion property and with the increase of rolling temperature,both electrochemical activity and anti-corrosion property of Al anode increase first and then decrease.When the rolling temperature is 420 ℃,the aluminum alloy anode has the most negative electrode potential of about-1.521 V(vs Hg/HgO)and the lowest hydrogen evolution rate of 0.171 6 mL/(min·cm2).The optimum comprehensive performance of Al alloy anode is obtained.     

Pulsed electrodeposition of hydroxyapatite on titanium substrate in solution containing hydrogen peroxide

Hydroxyapatite（HAP） coatings were prepared on the titanium substrate in the electrolyte containing H2O2 by the pulse electrodeposition. The introduction of H2O2 restrains the evolution of H2 and improves the adhesive strength between coatings and substrate. The results of pulse electrodeposition show that the relaxation time of the pulse is beneficial to growth of HAP because it makes ions diffuse from bulk to the surface of electrode and reduces concentration polarization in the next pulse time. It is beneficial to the increase of the duty circle of the pulse for deposition of HAP, but the result is not good if it is increased excessively. With increasing potential, it is good for the growth of HAP coatings. If the potential is too high, if is easy for HAP coatings to drop off during the process of electrodeposition under too intensive polarization, such as -1.0 V （vs SCE）, and there is not many coatings on the substrate. The combination of pulse electrodeposition and addition of hydrogen peroxide can assuredly improve the physico-chemical properties ofhydroxyapatite coatings.     

Ti-Cu层合电极的电解水析氢性能

目前通过使用粘接剂将催化剂粘接到基体上成为电解水析氢电极的主流制备方式,但粘接剂本身电阻较大且粘接强度低,易脱落。金属Pt是目前公认的最好的析氢金属电极,但其昂贵的价格限制了工业上大规模的使用。通过爆炸焊接技术将析气过电位低,稳定性好和强度高的钛与导电性优异的铜结合,构筑出一种自支撑钛-铜层合电极。电化学测试表明：相对于单一金属电极,钛-铜层合电极在1 mol/L KOH溶液中表现出良好的电解水析氢(HER)性能和导电性,且稳定性优异,在电流密度为10 mA·cm^-2,测试时间为20 000 s的稳定性测试中电位起伏只有0.05V。电解水析氢量测量实验结果中同样能够验证在实际工作中,钛-铜层合电极具备更优异的析氢性能。利用工作中产生的凹凸不平和富含孔洞的表面形貌暴露出更多的活性位点和电化学活性表面积,使得层合电极的HER性能在长时间工作中不会降低,还略有提高,这在电极材料有效制备且降低成本方面,具有广阔的工程应用前景。     

磷化时间与温度对镁合金磷化膜的影响

目的研究钙系磷化液的磷化温度及时间对磷化膜结构与性能的影响。方法通过控制单因素变量,在不同磷化温度和时间条件下在镁合金表面制备磷化膜。通过扫描电镜(SEM)、X射线衍射仪(XRD)以及极化曲线测试等方法对AZ31镁合金表面磷化膜的形貌、结构与性能进行分析。结果镁合金表面钙系磷化膜呈花瓣状结晶生长,其主要成分为CaHPO_4·2H_2O。随着磷化时间的增加,磷化膜的厚度不断增加,但磷化时间过长使得磷化膜的平整度有所下降。极化曲线测试分析表明,磷化时间为30 min时,腐蚀电位与极化电阻最大,腐蚀电流密度最小,此时磷化膜耐蚀性最佳。当磷化温度为30℃时,磷化膜致密性最好,磷化膜的结晶度及覆盖能力在磷化温度为30℃时达到最佳。极化曲线测试结果显示,磷化温度为30℃时的磷化膜极化电阻最大,腐蚀电流密度最小,耐蚀性最优。结论磷化时间为30 min、温度为30℃时所得磷化膜的质量最好,耐蚀性最佳。     

Comparison of rolled and heat treated SS304 in chloride solution using electrochemical and XPS techniques

SS304 in the rolled condition (66% cold work) and in the heat treated condition (solution quenched from 1100 °C) was assessed for its electrochemical behavior in de-aerated 3.5% NaCl by potentiodynamic polarization and AC impedance techniques. Surface analysis of films formed on the two materials in air and in solution was done using XPS. Open circuit potential (OCP) and pitting potential of the rolled SS304 were seen to be −0.25 V vs standard calomel electrode (SCE) and 0.25 V vs SCE respectively, while the heat treated sample showed −0.33 V vs SCE and 0.06 V vs SCE respectively. The rolled material showed a passive current density of 0.9 μA cm⁻², which was about one order lower than that shown by the heat treated material. The rolled material, in addition, exhibited repassivation at 0.085 V vs SCE during reverse scanning of potential. Repassivation was not observed in the heat tread sample. XPS showed that films on rolled material were richer in chromium as compared with those on heat treated alloy. Better passivation characteristics shown by the rolled material were attributed to thicker passive film with a higher Cr:Fe ratio, the higher Cr being the result of enhanced diffusion through the oriented grains in the rolled material.